Test Your Knowledge - Free MCQ PRACTICE
A fresh set of 20 random questions is generated every time you open this page and every time you refresh it.
For each of the following multiple choice questions, choose the most appropriate answer :

1. A spherical ball contracts in volume by 0.01% when subjected to a normal uniform pressure of 100 atmospheres. The built modulus of its material in dyne/cm square is
A. 2.0E11
B. 1E12
C. 100E12
D. 10E12

2. When a beta-particle is emitted from a nucleus, the neutron-proton ratio
A. is increased
B. is decreased
C. remains the same
D. first decreases then increases

3. What is the luminous intensity of a lamp which produces an illuminance of 12 lux at a distance of 5.0 m from it ?
A. 300 cd
B. 400 cd
C. 100 cd
D. 200 cd

4. Bermoulli's equation is a consequence of conservation of
A. Energy
B. Linear momentum
C. Angular momentum
D. Mass

5. Which energy-state of triply ionized beryllium Be+3 has the same orbital radius as that of state of hydrogen atom
A. n = 8 state
B. n = 5 state
C. n = 4 state
D. n = 2 state

6. A concave lens of focal length 20 cm placed in contact with a plane mirror acts as a
A. concave mirror of focal length 10 cm
B. concave mirror of focal length 60 cm
C. concave mirror of focal length 40 cm
D. convex mirror of focal length 10 cm

7. A good floor lamp has a wlde heavy base to increase its stability through
A. increasing contact area
B. lowering the center of gravity
C. raising the center of gravity
D. None of the above

8. When a compact disc is illuminated by a source of while light, coloured ‘lones’ are observed. This is due to
A. Dispersion
B. Diffraction
C. interference
D. Refraction

9. The maximum power rating of a 20 ohm resistor is 1 kW. If the integral resistance of the dc source is negligible, then this resistor can be safely used across a
A. 150 V dc source
B. 200 V dc source
C. 50 V dc source
D. None of these

10. Characteristic X-rays are produced due to
A. Transfer of momentum in collision of electrons with target atoms
B. Transition of electrons from higher to lower electronic orbits in an atom
C. Heating of the target
D. Transfer of energy in collision Ef electrons with atoms in the target

11. The Magnetic Resonance Imaging MRI is based on the phenomenon of
A. Nuclear magnetic resonance
B. Bectron spin resonance
C. Electron paramagnetic resonance
D. Diamagnetism of human tissues

12. A transformer is used to light a 140 watt, 24 volt lamp from 240 V A.C. mains. The current in the mains cable is 0.7 amp. The efficiency of the transformer is
A. 48%
B. '63.8%
C. 83.3%
D. 90%

13. The earth revolves about the sun in an elliptical orbit with mean radius 9.3E7 m in a period of 1 year. Assuming that there are no outside influences
A. The earth's kinetic energy remains constant
B. The earth’s potential energy remains constant
C. The earth's angular momentum remains constant
D. All three above are correct

14. A nucleus of mass number A, originally at rest, emits an alpha - particles with speed v. The daughter nucleus recoils with a speed
A. 2v/A + 4
B. 4v/A + 4
C. 4v/A - 4
D. 2v/A - 4

15. Consider an n-p-n transistor amplifier in common emitter configuration. The current gain of the transistor is 100. If the collector current changes by 1 mA, what will be the change in emitter current ?
A. 11.1mA
B. 1.01mA
C. 10 mA
D. 0.01 mA

16. A radio or T.V. set which uses valves does not start operating immediately when it switched on, whereas the set only containing transistors operates immediately. The reason for this is that
A. Current does not have so far to go in a transistor set
B. Filament of the value takes time to heat up
C. Valve set works at a higher voltage
D. Transistor set has a lower resistance

17. A bus is moving on a straight road towards north with a uniform speed of 50 km/hour when it turns through 90°. If the speed remains unchanged after turning, the increase in the Velocity of bus in the turning process is
A. 70.7 km/hour along south-west direction
B. zero
C. 50 km/hour along west
D. 70.7 km/hour along north-west direction

18. An ideal gas heat engine operates in a Carnot cycle between 227°C and 127°C. It absorbs 6 x 104 cal at the higher temperature. The amount of heat converted into work is
A. 4.8 x 104 cal
B. 1.2 x 104 cal
C. 3.5 x 104 cal
D. 1.6 x 104 cal

19. A stone of mass m is tied to a string of length l and rotated in a circle with a constant speed v. If the string is released, the stone flies
A. Tangential outward
B. Radically outward
C. Radially inward
D. With an acceleration mv2/l

20. The cyclotron frequency of an electron gyrating in a magnetic field of 1T is approximately
A. 28 MHz
B. 280 MHz
C. 2.8 GHz
D. 28 GHz

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