Model Questions for Engineering Entrance Tests Part - 4
( Physics) 

151. Electrons revolve in a circle with a frequency of 5 × 1014 Hz. The current due to this is
a. 5×1014 A
b. 8×10-5A
c. 3.2×10-31 A
d. zero
Ans: B

152. If the error in measurement of length and time is 2% the percentage error in velocity is
a. 1
b. 2
c. 4
Ans: C

153. At Mach number 2, the speed of an aeroplane will be:
a. half the speed of sound
b. double the speed of sound
c. four times the speed of sound
d. √2 times the speed of sound
Ans: B

154. In a stationary wave in air the variation of pressure at nodes is
a. maximum
b. minimum
c. three times the variation due to one wave alone
d. none of these
Ans: A

155. Out of the following the one without much variation of resistance with temperature is
a. copper
b. silicon
c. constantan
d. nichrome
Ans: C

156. A block has dimensions 10×8×4 cm. The ratio between maximum resistance to minimum resistance formed by the block is
a. 5:2
b. 25:4
c. 5:4
d. 1:1
Ans: B

157. The weight of an aeroplane in flight is balanced by:
a. the upthrust of air displaced
b. difference of pressure between the upper and lower surfaces of the wings created by he difference of speeds of air on the surfaces
c. vertical component of the thrust created by air currents striking the lower surface of the wings
d. force due to the reaction of gases ejected by the revolving propeller
Ans: B

158. The number which has order of magnitude 3 is
a. 5.01
b. 5000
c. 5001
d. 5.00
Ans: B

159. The weight of lead of R.D = 11 which will balance 8gm of iron of R.D = 8, when both are immersed in water is
a. 11 gm
b. 8 gm
c. 7.7 gm
d. 8.8 gm
Ans: C

160. Two copper wires have their lengths in the ratio 1:2 and radius 2:1. The ratio between their specific resistances is
a. 8:1
b. 4:1
c. 2:1
d. 1:1
Ans: D

161. The physical quantity which remains unchanged when a sound wave travels from one medium to another
a. speed
b. wavelength
c. amplitude
d. frequency
Ans: D

162. A bulb is marked 100 W, 250 V. Then
a. it always liberates 100J of light
b. it always draws 0.4 A current
c. its resistance is 625Ω
d. all the above are correct
Ans: C

163. 27 small liquid drops with radius 1 mm each are combined to form a single drop. The radius of this large drop is
a. 1 mm
b. 27 mm
c. 3 mm
d. 1.5 mm
Ans: C

164. A river is 120m wide and flows at a speed of 1 m/s. Two persons A and B can swim at 3 m/s. The approximate difference in time taken by them to cross the river if A crosses through shortest path and B in shortest time is
a. 1 s
b. 2 s
c. 3 s
d. 4 s
Ans: B

165. The tension in a sonometer wire is increased four times. The fundamental frequency becomes
a. 8 times
b. 2 times
c. 16 times
d. 10 times
Ans: B

166. The melting point of substances that contract on melting
a. decreases with increase in pressure
b. increases with increase in pressure
c. decreases at first and then increases with increase in pressure
d. is independent of pressure
Ans: A

167. A person travels along a straight road for the first half length with a velocity 40 m/s and the second half length with a velocity 60 m/s. The average velocity is given by
a. 0
b. 50 m/s
c. 48 m/s
d. 54 m/s
Ans: C

168. A spring stretched to a distance x has a PE=U. The additional energy required to stretch to a distance 2x is
a. U
b. 2U
c. 3U
d. 4U
Ans: C

169. The weight of a body in air is W. When it floats in water its weight is
a. W
b. W/2
c. zero
d. W/4
Ans: C

170. A cell is of emf 12 volts and internal resistance 2Ω. When it is short circuited the current is
a. zero
b. infinity
c. 12A
d. 6A
Ans: D

171. Two spheres of the same size are made of the same metal, but one is hollow ad the other is solid. They are heated to the same temperature:
a. both spheres will expand equally
b. the solid sphere will expand more than the hollow one
c. the solid sphere will expand but the hollow one will not
d. the hollow sphere will expand more than the solid one
Ans: A

172. The frequency of transverse vibration of a stretched string is 400 per second. If the tension is increased 4 times, its frequency will be:
a. 1600 per second
b. 100 per second
c. 200 per second
d. 800 per second
Ans: D

173. The best conductor of electric current is
a. silver
b. copper
c. aluminium
d. nichrome
Ans: A

174. A mixture of hydrogen and oxygen is taken in a container at constant temperature. The kinetic energy per molecule is
a. greater than oxygen
b. greater for hydrogen
c. same for both the gases
d. zero
Ans: C

175. Two vibrating systems are said to be in resonance if
a. their amplitudes are equal
b. their frequencies are equal
c. their damping factors are equal
d. their temperatures are the same
Ans: B

176. A boy throws an apple vertically up inside a train which is accelerating along a straight line. The apple
a. falls behind him
b. falls ahead him
c. returns straight to his hands
d. follows a parabolic path as observed by the boy
Ans: A

177. A stone projected with a velocity 100 m/s reaches the highest point in 5s. The angle of projection is
a. 00
b. 300
c. 450
d. 600
Ans: B

178. The percentage decrease in acceleration due to gravity when a body is taken to a height 32 km from the surface of the earth
a. 0%
b. 1%
c. 2%
d. 4%
Ans: B

179. When the area of cross section of a wire is halved and tension is doubled, the frequency becomes
a. same
b. two times
c. three times
d. four times
Ans: B

180. An instrument used for measuring the emf of a cell is
a. tacho meter
b. ammeter
c. metre bridge
d. volt meter
Ans: D

181. Two simple harmonic motions of same amplitude, same frequency and a phase difference of π results in the displacement of the particle along a
a. ellipse
b. circle
c. figure of eight
d. straight line
Ans: A

182. The dimensions of pressure gradient is
a. ML-2T-2
b. ML-2T-1
c. ML-1T-1
d. ML0T-2
Ans: C

183. A liquid shows capillary rise. Then its angle of contact is
a. acute
b. obtuse
c. 900
d. 00
Ans: A

184. Four equal resistances are connected to form a square. The effective resistance between any two diagonal points is 4Ω. The resistance of each side is
a. 4Ω
b. 8Ω
c. 2Ω
d. 16Ω
Ans: A

185. The following is an incorrect statement based on the first law of thermodynamics
a. The energy of an isolated system remains constant
b. The heat transfer equals the work plus the energy change
c. The heat transfer cannot exceed the work done
d. The net heat transfer equals the net work done for a cycle
Ans: C

186. When three bulbs A, B and C in the resistance ratio 1:2:3 are used separately in a house connection, the brightness is
a. largest for C
b. largest for B
c. largest for A
d. same for A, B and C
Ans: C

187. In which medium is the speed of sound maximum?
a. air
b. water
c. iron
d. interstellar space
Ans: C

188. Laplace corrected Newton's formula of velocity of sound because sound waves in air
a. Transverse
b. Propagate adiabatically
c. are longitudinal
d. propagate isothermally
Ans: B

189. A wire when connected across a source of emf liberates or dissipates 60J/s. When it is stretched to double its length, the heat liberated per second is
a. 30 J
b. 120 J
c. 15 J
d. 240 J
Ans: C

190. The excess of pressure inside one soap bubble is three times that inside a second soap bubble. Their volume are in the ratio
a. 1:81
b. 1:27
c. 1:3
d. 1:9
Ans: B

191. If the momentum of a body is increased by 60% its KE will be increased by
a. 50%
b. 100%
c. 125%
d. 156%
Ans: D

192. The order of (2)30 is approximately
a. 105
b. 109
c. 1015
d. 1020
Ans: B

193. A particle is thrown upward with a certain initial speed. It reaches the maximum height and subsequently returns back to the initial point. Through out its motion, the kinematical quantity which remains constant is
a. displacement
b. speed
c. velocity
d. acceleration
Ans: D

194. A man moves on a cycle horizontally with a velocity 4 km/hr. The rain is falling vertically with a velocity 3 km/hr. The direction in which he should hold the umbrella is
a. 370 with the vertical
b. 530 with the vertical
c. vertically
d. 450 with the vertical
Ans: B

195. The ratio of angular speeds of seconds hand and minutes hand of a watch is
a. 60:1
b. 1:60
c. 30:1
d. 1:30
Ans: A

196. The product of moment of inertia (M.I) and angular acceleration is
a. force
b. torque
c. work
d. angular momentum
Ans: B

197. A wire is drawn so that its radius becomes halved. Its new resistance
a. increases to four times
b. decreases to four times
c. increases to 16 times
d. decreases to 16 times
Ans: C

198. The difference between Cp and Cv is equal to the universal gas constant when
a. one gram of gas is heated
b. any amount of gas is heated
c. one molecule of gas is heated
d. one gram molecule is heated
Ans: D

199. Kirchoff's first law is related to
a. conservation of energy
b. conservation of momentum
c. conservation of angular momentum
d. conservation of charge
Ans: D

200. A wound watch spring
a. has no energy stored in it
b. has KE stored in it
c. has mechanical PE stored in it
d. has electrical energy stored in it
Ans: C