McqMate
| 101. |
The volume of a parallelepiped in Cartesian is |
| A. | dv = dx dy dz |
| B. | dv = dx dy |
| C. | dv = dy dz |
| D. | dv = dx dz |
| Answer» A. dv = dx dy dz | |
| 102. |
The scalar factor of Cartesian system is unity. State True/False. |
| A. | true |
| B. | false |
| Answer» A. true | |
| 103. |
The spherical equivalent of the vector B = yi + (x + z)j located at (-2,6,3) is given by |
| A. | (7,64.62,71.57) |
| B. | (7,-64.62,-71.57) |
| C. | (7,-64.62,71.57) |
| D. | (7,64.62,-71.57) |
| Answer» D. (7,64.62,-71.57) | |
| 104. |
Which of the following criteria is used to choose a coordinate system? |
| A. | distance |
| B. | intensity |
| C. | magnitude |
| D. | geometry |
| Answer» D. geometry | |
| 105. |
The cylindrical coordinate system is also referred to as |
| A. | cartesian system |
| B. | circular system |
| C. | spherical system |
| D. | space system |
| Answer» B. circular system | |
| 106. |
Transform the vector B=yi+(x+z)j located at point (-2,6,3) into cylindrical coordinates. |
| A. | (6.325,-71.57,3) |
| B. | (6.325,71.57,3) |
| C. | (6.325,73.57,3) |
| D. | (6.325,-73.57,3) |
| Answer» A. (6.325,-71.57,3) | |
| 107. |
Cylindrical systems have the following scalar values respectively |
| A. | 1, ρ ,1 |
| B. | 1, 1, 1 |
| C. | 0,1,0 |
| D. | 1,0,0 |
| Answer» A. 1, ρ ,1 | |
| 108. |
A charge located at point p (5,30⁰,2) is said to be in which coordinate system? |
| A. | cartesian system |
| B. | cylindrical system |
| C. | spherical system |
| D. | space system |
| Answer» B. cylindrical system | |
| 109. |
Cylindrical system is employed in waveguides. State True/False. |
| A. | true |
| B. | false |
| Answer» A. true | |
| 110. |
The pressure inside a piston cylinder is a variable of |
| A. | radius |
| B. | plane angle |
| C. | z plane distance |
| D. | constant, not a variable |
| Answer» C. z plane distance | |
| 111. |
Charges filled inside a cylindrical will possess flux in which direction? |
| A. | upwards |
| B. | downwards |
| C. | laterally outwards |
| D. | inwards |
| Answer» C. laterally outwards | |
| 112. |
Rectangular waveguides dominate the circular waveguides. Find the reason. |
| A. | low cut-off frequency |
| B. | easy to design |
| C. | more wave propagation |
| D. | the statement is false |
| Answer» B. easy to design | |
| 113. |
Convert the point (3,4,5) from Cartesian to spherical coordinates |
| A. | (7.07,45⁰,53⁰) |
| B. | (0.707,45⁰,53⁰) |
| C. | (7.07,54⁰,63⁰) |
| D. | (0.707,54⁰,63⁰) |
| Answer» A. (7.07,45⁰,53⁰) | |
| 114. |
Example of spherical system in the following is |
| A. | charge in space |
| B. | charge in box |
| C. | charge in dielectric |
| D. | uncharged system |
| Answer» A. charge in space | |
| 115. |
Spherical systems are employed in waveguides. State True/False |
| A. | true |
| B. | false |
| Answer» B. false | |
| 116. |
Choose which of following condition is not required for a waveguide to exist. |
| A. | the dimensions should be in accordance with desired frequency |
| B. | cut-off frequency should be minimum 6ghz |
| C. | the shape should be spherical |
| D. | no specific condition is required for waveguide design |
| Answer» C. the shape should be spherical | |
| 117. |
Find the spherical coordinates of A(2,3,-1) |
| A. | (3.74, 105.5⁰, 56.13⁰) |
| B. | (3.74, 105.5⁰, 56.31⁰) |
| C. | (3.74, 106.5⁰, 56.13⁰) |
| D. | (3.74, 106.5⁰, 56.31⁰) |
| Answer» B. (3.74, 105.5⁰, 56.31⁰) | |
| 118. |
Find the Cartesian coordinates of B(4,25⁰,120⁰) |
| A. | (0.845, 1.462, 3.625) |
| B. | (-0.845, 1.462, 3.625) |
| C. | (-8.45, 2.462, 6.325) |
| D. | (8.45, 2.462, 6.325) |
| Answer» B. (-0.845, 1.462, 3.625) | |
| 119. |
The area of sphere can be computed from the sphere volume. State True/False. |
| A. | true |
| B. | false |
| Answer» A. true | |
| 120. |
Given B= (10/r)i+( rcos θ) j+k in spherical coordinates. Find Cartesian points at (-3,4,0) |
| A. | -2i + j |
| B. | 2i + k |
| C. | i + 2j |
| D. | –i – 2k |
| Answer» A. -2i + j | |
| 121. |
The scalar factor of spherical coordinates is |
| A. | 1, r, r sin θ |
| B. | 1, r, r |
| C. | r, r, 1 |
| D. | r, 1, r |
| Answer» A. 1, r, r sin θ | |
| 122. |
The permittivity is also called |
| A. | electrostatic energy |
| B. | dielectric constant |
| C. | dipole moment |
| D. | susceptibility |
| Answer» B. dielectric constant | |
| 123. |
Dielectric constant will be high in |
| A. | conductors |
| B. | semiconductors |
| C. | insulators |
| D. | superconductors |
| Answer» C. insulators | |
| 124. |
Insulators perform which of the following functions? |
| A. | conduction |
| B. | convection |
| C. | provide electrical insulation |
| D. | allows current leakage at interfaces |
| Answer» C. provide electrical insulation | |
| 125. |
Find the susceptibility of a material whose dielectric constant is 2.26. |
| A. | 1.26 |
| B. | 3.26 |
| C. | 5.1 |
| D. | 1 |
| Answer» A. 1.26 | |
| 126. |
The susceptibility of free space is |
| A. | 1 |
| B. | 0 |
| C. | 2 |
| D. | ∞ |
| Answer» B. 0 | |
| 127. |
When the electric field becomes zero, which of the following relations hold good? |
| A. | e = p |
| B. | d = p |
| C. | b = p |
| D. | h = p |
| Answer» B. d = p | |
| 128. |
Which of the following are conductors? |
| A. | ceramics |
| B. | plastics |
| C. | mercury |
| D. | rubber |
| Answer» C. mercury | |
| 129. |
Find the range of band gap energy for conductors. |
| A. | >6 ev |
| B. | 0.2-0.4 ev |
| C. | 0.4-2 ev |
| D. | 2-6 ev |
| Answer» B. 0.2-0.4 ev | |
| 130. |
Conduction in metals is due to |
| A. | electrons only |
| B. | electrons and holes |
| C. | holes only |
| D. | applied electric field |
| Answer» A. electrons only | |
| 131. |
Find the band gap energy when a light of wavelength 1240nm is incident on it. |
| A. | 1ev |
| B. | 2ev |
| C. | 3ev |
| D. | 4ev |
| Answer» A. 1ev | |
| 132. |
Alternating current measured in a transmission line will be |
| A. | peak value |
| B. | average value |
| C. | rms value |
| D. | zero |
| Answer» C. rms value | |
| 133. |
The current in a metal at any frequency is due to |
| A. | conduction current |
| B. | displacement current |
| C. | both conduction and displacement current |
| D. | neither conduction nor displacement current |
| Answer» A. conduction current | |
| 134. |
For conductors, the free electrons will exist at |
| A. | valence band |
| B. | middle of valence and conduction band |
| C. | will not exist |
| D. | conduction band |
| Answer» D. conduction band | |
| 135. |
The current flowing through an insulating medium is called |
| A. | conduction |
| B. | convection |
| C. | radiation |
| D. | susceptibility |
| Answer» B. convection | |
| 136. |
Identify a good dielectric. |
| A. | iron |
| B. | ceramics |
| C. | plastic |
| D. | magnesium |
| Answer» B. ceramics | |
| 137. |
A dielectric can be made a conductor by |
| A. | compression |
| B. | heating |
| C. | doping |
| D. | freezing |
| Answer» B. heating | |
| 138. |
Find the dielectric constant for a material with electric susceptibility of 4. |
| A. | 3 |
| B. | 5 |
| C. | 8 |
| D. | 16 |
| Answer» B. 5 | |
| 139. |
For a dielectric which of the following properties hold good? |
| A. | they are superconductors at high temperatures |
| B. | they are superconductors at low temperatures |
| C. | they can never become a superconductor |
| D. | they have very less dielectric breakdown voltage |
| Answer» B. they are superconductors at low temperatures | |
| 140. |
he magnetic field which destroys the superconductivity is called |
| A. | diamagnetic field |
| B. | ferromagnetic field |
| C. | ferrimagnetic field |
| D. | critical field |
| Answer» D. critical field | |
| 141. |
The magnetic susceptibility in a superconductor will be |
| A. | positive |
| B. | negative |
| C. | zero |
| D. | infinity |
| Answer» B. negative | |
| 142. |
The superconducting materials will be independent of which of the following? |
| A. | magnetic field |
| B. | electric field |
| C. | magnetization |
| D. | temperature |
| Answer» B. electric field | |
| 143. |
Find the mean free path of an electron travelling at a speed of 18m/s in 2 seconds. |
| A. | 9 |
| B. | 36 |
| C. | 0.11 |
| D. | 4.5 |
| Answer» B. 36 | |
| 144. |
The best definition of polarisation is |
| A. | orientation of dipoles in random direction |
| B. | electric dipole moment per unit volume |
| C. | orientation of dipole moments |
| D. | change in polarity of every dipole |
| Answer» B. electric dipole moment per unit volume | |
| 145. |
Polarizability is defined as the |
| A. | product of dipole moment and electric field |
| B. | ratio of dipole moment to electric field |
| C. | ratio of electric field to dipole moment |
| D. | product of dielectric constant and dipole moment |
| Answer» B. ratio of dipole moment to electric field | |
| 146. |
Identify which type of polarisation depends on temperature. |
| A. | electronic |
| B. | ionic |
| C. | orientational |
| D. | interfacial |
| Answer» C. orientational | |
| 147. |
The total polarisation of a material is the |
| A. | product of all types of polarisation |
| B. | sum of all types of polarisation |
| C. | orientation directions of the dipoles |
| D. | total dipole moments in the material |
| Answer» B. sum of all types of polarisation | |
| 148. |
In the given types of polarisation, which type exists in the semiconductor? |
| A. | electronic |
| B. | ionic |
| C. | orientational |
| D. | interfacial or space charge |
| Answer» D. interfacial or space charge | |
| 149. |
Solids do not have which type of polarisation? |
| A. | ionic |
| B. | orientational |
| C. | interfacial |
| D. | electronic |
| Answer» C. interfacial | |
| 150. |
Which of the following is not an example of elemental solid dielectric? |
| A. | diamond |
| B. | sulphur |
| C. | silicon |
| D. | germanium |
| Answer» C. silicon | |
| 151. |
Compute the refractive index when the dielectric constant is 256 in air. |
| A. | 2562 |
| B. | 16 |
| C. | 256 |
| D. | 64 |
| Answer» B. 16 | |
| 152. |
Curie-Weiss law is applicable to which of the following materials? |
| A. | piezoelectric |
| B. | ferroelectric |
| C. | pyroelectric |
| D. | anti-ferroelectric |
| Answer» B. ferroelectric | |
| 153. |
Curie-Weiss law is used to calculate which one of the following? |
| A. | permittivity |
| B. | permeability |
| C. | electric susceptibility |
| D. | magnetic susceptibility |
| Answer» C. electric susceptibility | |
| 154. |
Calculate the loss tangent when the dielectric constant in AC field is given by 3 + 2j. |
| A. | (2/3) |
| B. | (3/2) |
| C. | (-3/2) |
| D. | (-2/3) |
| Answer» D. (-2/3) | |
| 155. |
When a dielectric loses its dielectric property, the phenomenon is called |
| A. | dielectric loss |
| B. | dielectric breakdown |
| C. | polarisation |
| D. | magnetization |
| Answer» B. dielectric breakdown | |
| 156. |
Choose the best definition of dielectric loss. |
| A. | absorption of electric energy by dielectric in an ac field |
| B. | dissipation of electric energy by dielectric in a static field |
| C. | dissipation of heat by dielectric |
| D. | product of loss tangent and relative permittivity |
| Answer» A. absorption of electric energy by dielectric in an ac field | |
| 157. |
The charge within a conductor will be |
| A. | 1 |
| B. | -1 |
| C. | 0 |
| D. | ∞ |
| Answer» C. 0 | |
| 158. |
For a conservative field which of the following equations holds good? |
| A. | ∫ e.dl = 0 |
| B. | ∫ h.dl = 0 |
| C. | ∫ b.dl = 0 |
| D. | ∫ d.dl = 0 |
| Answer» A. ∫ e.dl = 0 | |
| 159. |
Find the electric field if the surface density at the boundary of air is 10-9. |
| A. | 12π |
| B. | 24π |
| C. | 36π |
| D. | 48π |
| Answer» C. 36π | |
| 160. |
Find the flux density at the boundary when the charge density is given by 24 units. |
| A. | 12 |
| B. | 24 |
| C. | 48 |
| D. | 96 |
| Answer» B. 24 | |
| 161. |
The normal component of which quantity is always discontinuous at the boundary? |
| A. | e |
| B. | d |
| C. | h |
| D. | b |
| Answer» B. d | |
| 162. |
Find the permittivity of the surface when a wave incident at an angle 60 is reflected by the surface at 45 in air. |
| A. | 1.41 |
| B. | 3.5 |
| C. | 2.2 |
| D. | 1.73 |
| Answer» D. 1.73 | |
| 163. |
In free space, the Poisson equation becomes |
| A. | maxwell equation |
| B. | ampere equation |
| C. | laplace equation |
| D. | steady state equation |
| Answer» C. laplace equation | |
| 164. |
If Laplace equation satisfies, then which of the following statements will be true? |
| A. | potential will be zero |
| B. | current will be infinite |
| C. | resistance will be infinite |
| D. | voltage will be same |
| Answer» B. current will be infinite | |
| 165. |
Suppose the potential function is a step function. The equation that gets satisfied is |
| A. | laplace equation |
| B. | poisson equation |
| C. | maxwell equation |
| D. | ampere equation |
| Answer» A. laplace equation | |
| 166. |
The function V = exsin y + z does not satisfy Laplace equation. State True/False. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 167. |
Poisson equation can be derived from which of the following equations? |
| A. | point form of gauss law |
| B. | integral form of gauss law |
| C. | point form of ampere law |
| D. | integral form of ampere law |
| Answer» A. point form of gauss law | |
| 168. |
Find the charge density from the function of flux density given by 12x – 7z. |
| A. | 19 |
| B. | -5 |
| C. | 5 |
| D. | -19 |
| Answer» C. 5 | |
| 169. |
Find the electric field of a potential function given by 20 log x + y at the point (1,1,0). |
| A. | -20 i – j |
| B. | -i -20 j |
| C. | i + j |
| D. | (i + j)/20 |
| Answer» A. -20 i – j | |
| 170. |
When a material has zero permittivity, the maximum potential that it can possess is |
| A. | ∞ |
| B. | -∞ |
| C. | unity |
| D. | zero |
| Answer» D. zero | |
| 171. |
Work done in charging a capacitor is |
| A. | qv |
| B. | 1⁄2qv |
| C. | 2qv |
| D. | qv2 |
| Answer» B. 1⁄2qv | |
| 172. |
Energy stored in 2000mF capacitor charged to a potential difference of 10V is? |
| A. | 100j |
| B. | 200j |
| C. | 300j |
| D. | 400j |
| Answer» A. 100j | |
| 173. |
When do we get maximum energy from a set of capacitors? |
| A. | when they are connected in parallel |
| B. | when they are connected in series |
| C. | both in series and parallel |
| D. | insufficient information provided |
| Answer» A. when they are connected in parallel | |
| 174. |
Calculate the energy in the 2F capacitor. |
| A. | 8.6kj |
| B. | 64kj |
| C. | 64j |
| D. | 6.4kj |
| Answer» D. 6.4kj | |
| 175. |
Calculate the energy in the 4F capacitor. |
| A. | 128kj |
| B. | 1.28kj |
| C. | 12.8kj |
| D. | 1280j |
| Answer» C. 12.8kj | |
| 176. |
Calculate the energy stored in the combination of the capacitors. |
| A. | 192kj |
| B. | 1.92kj |
| C. | 19.2kj |
| D. | 1920j |
| Answer» C. 19.2kj | |
| 177. |
The unit for dielectric strength is |
| A. | v/m2 |
| B. | mv/m2 |
| C. | mv/m |
| D. | vm |
| Answer» C. mv/m | |
| 178. |
If the Voltage increases, what happens to dielectric strength? |
| A. | increases |
| B. | decreases |
| C. | remains the same |
| D. | becomes zero |
| Answer» A. increases | |
| 179. |
If the thickness of the material increases, what happens to the dielectric strength? |
| A. | increases |
| B. | decreases |
| C. | remains the same |
| D. | becomes zero |
| Answer» B. decreases | |
| 180. |
Which medium has the highest dielectric strength? |
| A. | water |
| B. | mica |
| C. | air |
| D. | glass |
| Answer» C. air | |
| 181. |
Leakage in capacitors is primarily caused by |
| A. | transistors |
| B. | resistors |
| C. | inductors |
| D. | dc motors |
| Answer» A. transistors | |
| 182. |
What is the conduction current when a capacitor is fully charged? |
| A. | infinity |
| B. | zero |
| C. | 100a |
| D. | 1000a |
| Answer» B. zero | |
| 183. |
The flow of electrons in dielectric is due to |
| A. | conduction |
| B. | potential difference |
| C. | breakdown |
| D. | resistance |
| Answer» C. breakdown | |
| 184. |
The flow of electrons which does not pass through the battery is known as |
| A. | displacement current |
| B. | leakage current |
| C. | either displacement or leakage current |
| D. | neither displacement nor leakage current |
| Answer» A. displacement current | |
| 185. |
The free electrons in practical dielectrics is due to _ |
| A. | there are no free electrons |
| B. | conductors |
| C. | impurities |
| D. | both conductors and impurities |
| Answer» C. impurities | |
| 186. |
What is the type of current where the electrons actually move? |
| A. | displacement current |
| B. | conduction current |
| C. | both conduction and displacement current |
| D. | neither conduction nor displacement current |
| Answer» B. conduction current | |
| 187. |
What is the type of current caused due to variations in the field? |
| A. | displacement current |
| B. | conduction current |
| C. | both conduction and displacement current |
| D. | neither conduction nor displacement current |
| Answer» A. displacement current | |
| 188. |
Under normal conditions capacitors have _ |
| A. | displacement current |
| B. | conduction current |
| C. | both conduction and displacement current |
| D. | neither conduction nor displacement current |
| Answer» A. displacement current | |
| 189. |
Under normal conditions capacitors have _ |
| A. | displacement current |
| B. | conduction current |
| C. | both conduction and displacement current |
| D. | neither conduction nor displacement current |
| Answer» A. displacement current | |
| 190. |
What is the unit for displacement current? |
| A. | no unit |
| B. | ampere |
| C. | coulomb |
| D. | ampere/coulomb |
| Answer» B. ampere | |
| 191. |
Displacement current depends on _ |
| A. | moving charges |
| B. | change in time |
| C. | both moving charges and change in time |
| D. | neither moving charges nor change in time |
| Answer» B. change in time | |
| 192. |
Magnetic fields between the parallel plates of a capacitor are due to? |
| A. | displacement current |
| B. | conduction current |
| C. | both conduction and displacement current |
| D. | neither conduction nor displacement current |
| Answer» A. displacement current | |
| 193. |
The free electrons in practical dielectrics are due to |
| A. | there are no free electrons |
| B. | conductors |
| C. | impurities |
| D. | displacement currents |
| Answer» C. impurities | |
| 194. |
Paper capacitor is a type of _ |
| A. | fixed capacitor |
| B. | variable capacitor |
| C. | either fixed or variable depending on its usage |
| D. | neither fixed nor variable |
| Answer» A. fixed capacitor | |
| 195. |
A capacitor using chemical reactions to store charge is _ |
| A. | paper capacitor |
| B. | ceramic capacitor |
| C. | polyester capacitor |
| D. | electrolyte capacitor |
| Answer» D. electrolyte capacitor | |
| 196. |
Which, among the following, is the odd one out? |
| A. | ceramic capacitor |
| B. | electrolyte capacitor |
| C. | tuning capacitor |
| D. | paper capacitor |
| Answer» C. tuning capacitor | |
| 197. |
In a variable capacitor, capacitance can be varied by |
| A. | turning the rotatable plates in or out |
| B. | sliding the rotatable plates |
| C. | changing the plates |
| D. | changing the material of plates |
| Answer» A. turning the rotatable plates in or out | |
| 198. |
The simplest kind of capacitor is _ |
| A. | ceramic capacitor |
| B. | electrolyte capacitor |
| C. | tuning capacitor |
| D. | paper capacitor |
| Answer» D. paper capacitor | |
| 199. |
Capacitor preferred when there is high frequency in the circuits is _ |
| A. | electrolyte capacitor |
| B. | mica capacitor |
| C. | air capacitor |
| D. | glass capacitor |
| Answer» B. mica capacitor | |
| 200. |
The type of capacitors used in communication transmitters are? |
| A. | electrolyte capacitor |
| B. | variable capacitor |
| C. | air capacitor |
| D. | glass capacitor |
| Answer» B. variable capacitor | |
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