McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: General Knowledge (GK) .
| 651. |
An object with a constant speed – |
| A. | is not accelerated |
| B. | might be accelerated |
| C. | is always accelerated |
| D. | also has a constant velocity |
| Answer» A. is not accelerated | |
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Explanation: Acceleration is defined as the rate at which an object changes its velocity. An object is accelerating if it is changing its velocity. An object with constant speed will have no acceleration as the speed is uniform. |
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| 652. |
The instrument used to regulate temperature to a particular degree is called : |
| A. | Thermostat |
| B. | Thermometer |
| C. | Pyrometer |
| D. | Thermocouple |
| Answer» A. Thermostat | |
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Explanation: A thermostat is a component which senses the temperature of a system so that the system's temperature is maintained near a desired set point. At its core, a thermostat is simply the controls used to regulate temperature in a heating system. |
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| 653. |
The power dissipated in a resistance is given by? |
| A. | V²/R |
| B. | IV |
| C. | All of these |
| D. | I²R |
| Answer» C. All of these | |
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Explanation: Any resistor in a circuit that has a voltage drop across it dissipates electrical power. This electrical power is converted into heat energy hence all resistors have a power rating. |
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| 654. |
The technique used by bats to find their way or to locate food is . |
| A. | SONAR |
| B. | RADAR |
| C. | Echolocation |
| D. | Flapping |
| Answer» C. Echolocation | |
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Explanation: Bats use echolocation to navigate and find food in the dark. To echolocate, bats send out sound waves from their mouth or nose. When the sound waves hit an object they produce echoes. |
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| 655. |
In the absence of the earth's atmosphere, sky would appear – |
| A. | blue |
| B. | deep red |
| C. | white |
| D. | black |
| Answer» D. black | |
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Explanation: Sky appears blue because the tiny particles of the earth's atmosphere scatter the blue colour (short wavelength) of the sunlight more dominantly than other wavelengths. A blue sky is a manifestation of Rayleigh scatter. The sky would appear black in the absence of earth's atmosphere because there would be no particles to scatter the light. |
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| 656. |
If ice floating on water in a vessel melts, the water level in the vessel - |
| A. | increases |
| B. | does not change |
| C. | first increases before decreasing |
| D. | decreases |
| Answer» B. does not change | |
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Explanation: When ice floating on water in a vessel melts, the water level in the vessel does not change. This is because when floating, the ice displaces an amount of water equal to its mass, and when melted, it becomes an amount of water equal to its mass. It is accordance with Archimedes Principle, which states that the mass of the liquid displaced by a floating object is equivalent to the mass of the object. |
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| 657. |
One micron is equal to- |
| A. | 1/10th of mm |
| B. | 1/100th of mm |
| C. | 1/1000th of mm |
| D. | 1/10000th of mm |
| Answer» C. 1/1000th of mm | |
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Explanation: In the U.S. the thickness of paint is expressed in mils (one mil equals 1/1000 of inch). The rest of the world expresses coating thickness in microns (1 micron = 1 millionth of a meter and 25.4 microns = .001” inch or 1 mil). |
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| 658. |
Quality of a musical note depends on – |
| A. | Fundamental frequency |
| B. | Amplitude of the wave |
| C. | Harmonics present |
| D. | Velocity of sound in the medium |
| Answer» C. Harmonics present | |
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Explanation: Sound "quality" or "timbre" describes those characteristics of sound which allow the ear to distinguish sounds which have the same pitch and loudness. Timbre is mainly determined by the harmonic content of a sound and the dynamic characteristics of the sound such as vibrato and the attack-decay envelope of the sound. Harmonic content is the most important of these. |
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| 659. |
Silicon is used in which of the following? |
| A. | Semiconductors |
| B. | solar energy devices |
| C. | transistors |
| D. | All of these |
| Answer» D. All of these | |
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Explanation: Silicon is a chemical element (its symbol in chemical formula expressions is "Si") that is present in sand and glass and which is the best known semiconductor material in electronic components. Its atomic number is 14. |
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| 660. |
The frequency of direct current is . |
| A. | Zero |
| B. | 50 HZ |
| C. | 60 HZ |
| D. | 100 HZ |
| Answer» A. Zero | |
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Explanation: Direct Current (DC) refers to power systems that use only one polarity of voltage or current, and to refer to the constant, zero-frequency, or slowly varying local mean value of a voltage or current. |
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| 661. |
For photoelectric effect to take place, the metal used as the cathode should have – |
| A. | high melting point |
| B. | low melting point |
| C. | low work function |
| D. | low resistance |
| Answer» C. low work function | |
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Explanation: The photoelectric effect is the propensity of high-energy electromagnetic radiation to eject electrons from a given material. The photoelectric effect has been utilized in devices called photocells, consisting of two electrodes in a sealed vacuum tube. |
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| 662. |
If electric resistance is to be decreased, then the number of resistances should be connected in – |
| A. | Series |
| B. | Parallel |
| C. | Mixed arrangement |
| D. | None of these |
| Answer» B. Parallel | |
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Explanation: Resistors are in parallel when each resistor is connected directly to the voltage source by connecting wires having riegligible resistance. Each resistor thus has the full voltage of the source applied to it. When resistors are connected in parallel, more current flows from the source than would flow for any of them individually, so the total resistance is lower. Each resistor in parallel has the same full voltage of the source applied to it, but divide the total current amongst them |
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| 663. |
The material used in electric heater is |
| A. | Tungsten |
| B. | Nichrome |
| C. | Brass |
| D. | Steel |
| Answer» B. Nichrome | |
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Explanation: Due to its resistance to oxidation and stability at high temperatures, Nichrome is widely used in electic heating elements, such as in appliances and tools. Typically, nichrome is wound in coils to a certain electrical resistance, and current is passed through it to produce heat. |
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| 664. |
The rate of change of displacement is called: |
| A. | Acceleration |
| B. | Speed |
| C. | Distance |
| D. | Velocity |
| Answer» D. Velocity | |
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Explanation: In considering motions of objects over time the instantaneous velocity of the object is the rate of change of the displacement as a function of time. |
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| 665. |
The direction of heat flow between two objects depends on - |
| A. | Their masses |
| B. | Their heat contents |
| C. | Their temperatures |
| D. | Whether they are in solid, liquid or gaseous state |
| Answer» C. Their temperatures | |
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Explanation: Heat always flows from a body at higher temperature to a body at a lower temperature. |
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| 666. |
A man in a train moving with a constant velocity drops a ball on the platform. The path of the ban as seen by an observer standing on the platform is – |
| A. | A straight line |
| B. | A circle |
| C. | A parabola |
| D. | None of these |
| Answer» C. A parabola | |
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Explanation: In the reference frame of the platform the ball has initial horizontal velocityequal to the velocity of the train. The vertical direction is the same observed on the train because both observers agree that gravity is acting on the ball causing an acceleration g. |
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| 667. |
Which of the following is responsible for permanent hardness of water? |
| A. | magnesium bicarbonate |
| B. | sodium chloride |
| C. | calcium sulphate |
| D. | calcium bicarbonate |
| Answer» C. calcium sulphate | |
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Explanation: Permanent hardness is caused by dissolved calcium sulfate (which is not removed by boiling). Hard water contains dissolved magnesium and calcium ions. These make it more difficult for the water to form lather with soap. Temporary hardness is caused by dissolved calcium hydrogen carbonate (which is removed by boiling) |
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| 668. |
While ascending a hill, the driver of the vehicle keeps the gear ratio – |
| A. | equal to 1 |
| B. | less than 1 |
| C. | greater than 1 |
| D. | either equal to or greater than 1 |
| Answer» D. either equal to or greater than 1 | |
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Explanation: While ascending a hill Gear Ratio should be "Either equal to or greater than 1?. Gear Ratio is the ratio between angular velocity of input gear to the angular velocity of output gear. It prevents the vehicle from stalling. |
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| 669. |
A wire of resistance R is cut into ‘n’ equal parts. These parts are then connected in parallel. The equivalent resistance of the combination will be – |
| A. | nR |
| B. | R/n |
| C. | n/R |
| D. | R/n² |
| Answer» D. R/n² | |
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Explanation: Since R is directly proportional to length of the wire, when wire is cut into equal parts, then Resistance of each part = R/n |
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| 670. |
What is unit of Electrical Capacity? |
| A. | henry |
| B. | farad |
| C. | volt |
| D. | ohm |
| Answer» B. farad | |
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Explanation: Henry is unit of Magnetic Induction, volt is unit of Potential Difference, ohm is unit of Electric Resistance. |
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| 671. |
Work done upon a body . |
| A. | only a vector quantity |
| B. | only a scalar quantity |
| C. | both vector and scalar |
| D. | neither vector nor scalar |
| Answer» B. only a scalar quantity | |
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Explanation: 0 |
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| 672. |
With the increase of pressure, the boiling point of any substance - |
| A. | Increases |
| B. | Decreases |
| C. | Remains Same |
| D. | Becomes zero |
| Answer» A. Increases | |
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Explanation: The temperature stays the same until all the liquid has vaporized. As the temperature of a liquid rises, the pressure of escaping vapor also rises, and at the boiling point the pressure of the escaping vapor is equal to that exerted on the liquid by the surrounding air, causing bubbles to form. |
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| 673. |
When a particle and an antiparticle come in contact with each other, they |
| A. | repell each other |
| B. | annihilate each other |
| C. | go undisturbed |
| D. | spin about a common axis |
| Answer» B. annihilate each other | |
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Explanation: 0 |
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| 674. |
Photon is the fundamental unit/ quantum of – |
| A. | gravitation |
| B. | electricity |
| C. | magnetism |
| D. | light |
| Answer» D. light | |
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Explanation: A photon is an elementary particle, the quantum of light and all other forms of electromagnetic radiation. The modern photon concept was developed gradually by Albert Einstein. |
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| 675. |
Time of exposure required for taking photograph of an object depends upon the – |
| A. | brightness of the object |
| B. | skill of photographer |
| C. | proximity of object |
| D. | size of the object |
| Answer» A. brightness of the object | |
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Explanation: In photography, shutter speed or exposure time is the effective length of time a camera's shutter is open. The total exposure is proportional to this exposure time, or duration of light reaching the film or image sensor. The correct exposure for a particular object dependson the brightness of the object to be photographed. |
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| 676. |
The ordinary and maximum tolerance limit of sound by human being is – |
| A. | 50 db to 70 db (decibel) |
| B. | 60 db to 80 db (decibel) |
| C. | 65 db to 75 db (decibel) |
| D. | 70 db to 85 db (decibel) |
| Answer» B. 60 db to 80 db (decibel) | |
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Explanation: Normal speech is about 60 dB (decibels). A dangerous sound is anything that is 80 dB or higher which can lead to hearing loss. At 70 dB or lower, the risk of harm to healthy ears is negligible. Listening to sound above 80 decibels can cause profound deafness. |
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| 677. |
Which is best used as a sound absorbing material in partition walls? |
| A. | Stone chips |
| B. | Steel |
| C. | Glass - wool |
| D. | Glass pieces |
| Answer» C. Glass - wool | |
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Explanation: Materials that do not transfer mechanical energy well. These tend to be soft, flexible, low density, and with high surface area to linear area ratios. |
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| 678. |
The best conductor of electricity among the following is - |
| A. | copper |
| B. | iron |
| C. | aluminum |
| D. | silver |
| Answer» D. silver | |
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Explanation: Copper and Silver Are Most Common. Silver is the best conductor of electricity because it contains a higher number of movable atoms (free electrons). |
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| 679. |
Light Emitting Diodes (LED) is used in fancy electronic devices such as toys emit |
| A. | X-rays |
| B. | ultraviolet light |
| C. | (4) All of the above |
| D. | radio waves |
| Answer» D. radio waves | |
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Explanation: A light-emitting diode (LED) is a semiconductor light source that emits light when current flows through it. Infrared LEDs are used in remote-control circuits, such as those used with a wide variety of consumer electronics. |
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| 680. |
The primary colours in photography are – |
| A. | Red, Blue, Yellow |
| B. | Red, Yellow, Green |
| C. | Red, Blue, Green |
| D. | Blue, Yellow, Green |
| Answer» A. Red, Blue, Yellow | |
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Explanation: There are three primary colours of Red, Green and Blue (ROB). As these are mixed they form lighter colours, and when all three are mixed together they appear as white. Artists and graphic designers, who work with paintings and illustrations more than they do with photographs, often refer to Red, Yellow and Blue as the primary colours. |
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| 681. |
Two electrons in an orbital are differentiated by which of the following? |
| A. | Magnetic quantum number |
| B. | Spin quantum number |
| C. | Principal quantum number |
| D. | Azimuthal quantum number |
| Answer» B. Spin quantum number | |
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Explanation: Spin quantum number is the fourth quantum number that differentiates two electrons in the same orbital. |
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| 682. |
Stress can be defined as quantity. |
| A. | Scalar |
| B. | Vector |
| C. | Phasor |
| D. | Tensor |
| Answer» D. Tensor | |
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Explanation: Stress is defined as Resisting force per unit area of an element, on which load is applied. Stress is always perpendicular to a cross-section in the element. It is neither scalar (it cannot be numerically added), nor is it a vector (it does not follow the triangle rule of vector addition). It is a tensor quantity because it describes things happening in two directions simultaneously. |
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| 683. |
Which of the following property of sound is affected by change in air temperature – |
| A. | Frequency |
| B. | Intensity |
| C. | Amplitude |
| D. | Wavelength |
| Answer» D. Wavelength | |
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Explanation: The wavelength of sound changes with temperature. This is because the speed of sound changes with the temperature. Since the speed of sound is different at different temperature, this means the wavelength of sound at a given frequency is a variable depending on the speed of sound. For example, the wavelength of a 100 cycle tone in air at 68°F would be 11.27 feet while the same tone in fresh water at 68°F would have a wavelength of 48.05 feet. |
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| 684. |
Vehicles use to see the objects coming from behind. |
| A. | Concave lens |
| B. | Convex lens |
| C. | Convex mirror |
| D. | Concave mirror |
| Answer» B. Convex lens | |
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Explanation: Convex mirror is used in rear view mirror of vehicles; so that the driver can see the traffic coming from behind. The field of view is widest in case of a convex mirror, which enables it to show a wider area from behind. |
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| 685. |
If electrical conductivity increases with the increase of temperature of a substance, then it is a: |
| A. | Conductor |
| B. | Semiconductor |
| C. | Insulator |
| D. | Carborator |
| Answer» B. Semiconductor | |
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Explanation: A solid substance that has conductivity between that of an insulator and that of most metals, either due to the addition of an impurity or because of temperature effects |
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| 686. |
Transition ions absorb light in – |
| A. | infrared region |
| B. | ultraviolet region |
| C. | microwave region |
| D. | visible region |
| Answer» D. visible region | |
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Explanation: Transition metal ions have an incomplete set of 3d electrons. Changes in the energy of these electrons correspond to the energy of visible light. The absorption of visible light by these ions lend colour to gems. |
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| 687. |
If a body weighs 12N on the surface of the earth, how much will it weigh on the surface of the moon where acceleration due to gravity is only one-sixth of that on earth's surface? |
| A. | 12N |
| B. | 2N |
| C. | 10N |
| D. | 6N |
| Answer» B. 2N | |
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Explanation: Weight is mass x g. Since mass is constant and g is only 16thof that on the earth. The weight on the moon is only 16th of that on the earth. |
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| 688. |
'Kilowatt-hour' is the unit of - |
| A. | potential difference |
| B. | electric power |
| C. | electric energy |
| D. | electric potential |
| Answer» C. electric energy | |
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Explanation: The kilowatt hour (symbolized kW h as per SI) is a composite unit of energy equivalent to one kilowatt (1 kW) of power sustained for one hour. |
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| 689. |
If the temperature inside a room is increased, the relative humidity will ? |
| A. | increase |
| B. | decrease |
| C. | remain unchanged |
| D. | none of these |
| Answer» B. decrease | |
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Explanation: This is because temperatures in the home can be much different than the temperature outside. This is because of that important relationship between temperature and how much maximum moisture can be in the air. |
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| 690. |
The device used to change the speed of an electric fan is - |
| A. | Amplifier |
| B. | Regulator |
| C. | Switclh |
| D. | Rectifier |
| Answer» B. Regulator | |
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Explanation: Regulator is to adjust the voltage across the motor of the fan. |
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| 691. |
The required DC voltage for arc welding is- |
| A. | 6 to 9 V |
| B. | 50 to 60 V |
| C. | 200 to 250 V |
| D. | 90 to 100 V |
| Answer» C. 200 to 250 V | |
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Explanation: 0 |
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| 692. |
What is the base of the Octal Numeral System? |
| A. | 8 |
| B. | 16 |
| C. | 32 |
| D. | 64 |
| Answer» A. 8 | |
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Explanation: The octal numeral system is the base-8 number system and uses the digits 0 to 7. As it uses only eight digits (0 through 7) there are no numbers or letters used above 8. |
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| 693. |
A wire carrying current is – |
| A. | positively charged |
| B. | negatively charged |
| C. | neutral |
| D. | charged with a type depending upon current strength |
| Answer» C. neutral | |
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Explanation: 0 |
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| 694. |
A light ray travelling from denser to rarer medium at an angle of incidence more than critical angle of concerned media pair suffers. |
| A. | reflection |
| B. | refraction |
| C. | diffraction |
| D. | total internal reflection |
| Answer» D. total internal reflection | |
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Explanation: If the angle of incidence of light ray in the denser medium is greater than the critical angle of the concerned media pair, the light is not at all reflected in to the rarer medium but is totally reflected. This is known as 'total internal reflection'. |
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| 695. |
Which of the following physical quantities has no dimension? |
| A. | Force |
| B. | Momentum |
| C. | Impulse |
| D. | Angle |
| Answer» D. Angle | |
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Explanation: Quantities having units, but no dimensions: Plane angle, angular displacement, solid angle. These physical quantities possess units but they does not possess dimensional formulas. |
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| 696. |
Which of the following is a good conductor of heat but bad conductor of electricity? |
| A. | mica |
| B. | asbestos |
| C. | celluloid |
| D. | paraffin wax |
| Answer» A. mica | |
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Explanation: Mica is a good conductor of heat but bad conductor of electricity. |
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| 697. |
Respiration in the absence of air is called - |
| A. | Aerobic respiration |
| B. | Anaerobic respiration |
| C. | Muscular respiration |
| D. | Molecular respiration |
| Answer» B. Anaerobic respiration | |
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Explanation: Respiration in the absence of air is called Anaerobic respiration while respiration in the presence of air (oxygen) is called aerobic respiration. |
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| 698. |
Which one among the following is responsible for formation of "Ozone Holes" in the atmosphere? |
| A. | Benzopyrene |
| B. | Hydrocarbons |
| C. | Chlorofluorocarbons |
| D. | UV radiation |
| Answer» C. Chlorofluorocarbons | |
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Explanation: Chlorofluorocarbon (CFCs), commonly known by the DuPont brand name Freon, are considered as one of the ozone- depleting substances. |
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| 699. |
An alloy is an example of : |
| A. | Colloidal solution |
| B. | Emulsion |
| C. | Solid solution |
| D. | Heterogeneous mixture |
| Answer» C. Solid solution | |
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Explanation: A Solid solution is a uniform mixture of substances in solid form. |
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| 700. |
Hydrogen atom is excited from ground state to another state with principal quantum number equal to 4. Then the number of spectral lines in the emission spectra will be - |
| A. | 2 |
| B. | 6 |
| C. | 5 |
| D. | 3 |
| Answer» B. 6 | |
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Explanation: Number of spectral lines from a state n to ground state is = n (n-1)/2 =4(4-1)/2=12/2 =6 |
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