09-06-2012, 11:32 AM
Physics Question paper
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1.Which of the following is not an electro magnetic wave
a) x-rays b) alpha-rays c) gamma-rays d) light rays
2.Electro magnetic waves of wave length ranging from 100Åto 4000Å come under
a) x-rays b) UV region c) visible region d) n infra-red region
3.Electro magnetic theory suggests that the light consists of
a) magnetic vector alone b) electric vector alone c) electric
and magnetic vectors perpendicular to each other. d) parallel electric and magnetic vector
4.The frequency of radio waves corresponding to a wave length of 10 m is
a) 3×107Hz b) 3.3×108Hz c) 3×109Hz d) 3×10−7Hz
5.The electromagnetic waves travel with velocity of
a) sound b) light c) greater than that of light d) greater than that of sound
6.The existence of EM waves were experimentally confirmed by
a) Maxwell b) Faraday c) Hertz d) Tesla
7.The back emf in a DC motor is maximum when
a) the motor has picked up maximum speed b) the motor has just
started moving c) the speed of motor is still on increase d) the motor has just been switched off
8.AC measuring instrument measures
a) peak value b) rms value c) any value d) average value
9.The Q-factor of a resonant circuit is equal to
a) 1CWR b) 1WL c) CWR d) fCW
10.In a step-down transformer, the number of turns in
a) Primary are less b) Primary are more c) Primary
and secondary equal d) secondary are infinite
11.In AC circuits choke is preferred to resistors because
a) choke coil is cheap b) voltage increases c) energy
is not wasted d) current increases
12.A choke is used as resistance in
a) AC circuits b) DC circuits c) half-wave rectifier
circuits d) both AC and DC circuits