McqMate

55

56.5k

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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