Competitive Exams Physics Objective Questions Part 4

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Q-1. Rectifier converts

(a) Mechanical energy to electrical energy

(b) A. C to D. C

(c) Light energy to electrical energy

(d) None of these

Q-2. What is the dimension of




(d) Unit less

Q-3 For formation of permanent magnets, the material should have

(a) High coercively

(b) Low coercively

(c) High retentivity

(d) Both (a) and (c)

Q-4. In order to obtain a real image of magnification 2 using a converging lens of focal length 20 cm, where should be an object be placed?





Q-5. A ball is dropped from a height of 20 cm. Ball rebounds to a height of 10 cm. What is the loss of energy?

(a) 25 %

(b) 75 %

(c) 50 %

(d) 100 %

Q-6. When you move from equator to pole, the value of acceleration due to gravity (g)

(a) Increases

(b) Decreases

(c) Remains the same

(d) Increases then decreases.

Q-7. A simple pendulum has time period T. The bob is given negative charge and surface below it is given positive charge. The new time period will be

(a) less than T

(b) Greater than T

(c) Equal to T

(d) infinite

Q-8. A bullet loses 1/20 of its velocity after penetrating a plank. How many plank are required to stop the bullet?

(a) 6

(b) 9

(c) 11

(d) 13

Q-9. An aero plane 400 m from north and 300 m south and then flies 1200 m upwards, then net displacement is

(a) 1200 m

(b) 1300 m

(c) 1400 m

(d) 1500 m

Q-10. Which law follows the law of conservation of energy?

(a) Lenz՚s law

(b) Kirchhoff՚s law

(c) Maxwell՚s law

(d) Ampere՚s law

Q-11. Isogonics lines on magnetic map have

(a) Zero angle of dip

(b) Zero angle of declination

(c) Same angle of declination

(d) Same angle of dip

Q-12. Pressure gradient has the same dimension as that of

(a) Velocity gradient

(b) Energy gradient

(c) Potential gradient

(d) None of these

Q-13. If fundament frequency of closed pipe is 50 Hz, then frequency of 2nd overtone is

(a) 100 Hz

(b) 50 Hz

(c) 250 Hz

(d) 150 Hz

Q-14. A boat of mass 40 kg is at rest. A dog of mass 4 kg moves in the boat with a velocity of 10 m/s. What is the velocity of boat?





Q-15. Which of the following has negative temperature coefficient of resistance?

(a) Copper

(b) Aluminum

(c) Iron

(d) Germanium

Q-16 At which place, earth՚s magnetism become horizontal?

(a) Magnetic pole

(b) Geographical pole

(c) Magnetic meridian

(d) Magnetic equator

Q-17. Magnetic dipole moment is a

(a) Scalar quantity

(b) Vector quantity

(c) Constant quantity

(d) None of these

Q-18. What is the shape when a non-wetting liquid is placed in a capillary tube?

(a) Concave upward

(b) Convex upward

(c) Concave downward

(d) Convex downward

Q-19. Application of Bernoulli՚s theorem can be seen in

(a) Dynamic lift of aero plane

(b) Hydraulic press

(c) Helicopter

(d) None of these

Q-20. Unit of reduction factor is

(a) ampere

(b) Ohms

(c) Teals

(d) Weber

Q-21. Huygens wave theory allows us to know

(a) The wavelength of the wave

(b) The velocity of the wave

(c) The amplitude of the wave

(d) The propagation of wave fronts


Q-22. Which of the following is secondary cell?

(a) Voltaic cell

(b) Daniel cell

(c) Leclanche cell

(d) Edison cell

Q-23. Poisson՚s ration cannot have the value

(a) Air

(b) Iron

(c) Air and iron

(d) None of these

Q-24. if a thermometer reads freezing point of water as and boiling point as how much thermometer read when the actual temperature is





Q-25. Apparatus used to find out velocity of sound in gas is

(a) Meade՚s apparatus

(b) Kundt՚s tube

(c) Quince՚s tube

(d) none of these

Q-26. When the atmospheric temperature becomes nearly equal to the dew point, then

(a) Relative humidity is 100 %

(b) Relative humidity is 90 %

(c) Relative humidity is 50 %

(d) Nothing can be said

Q-27. Current provided by a battery is maximum when

(a) Internal resistance equal to external resistance

(b) Internal resistance is greater than external resistance

(c) Internal resistance is less than external resistance

(d) None of these

Q-28. If the temperature of atmosphere is increased the following character of sound waves is affected.

(a) Amplitude

(b) Frequency

(c) Velocity

(d) Wave length

Q-29. A thin aluminum sheet is placed between the plates of a parallel plate capacitor. Its capacitance will

(a) Increases

(b) Decreases

(c) Remain same

(d) Become infinite

Q-30. A heater coil connected to a supply of a 220 V dissipating some power The coil is cut into half and the two halves are connected in parallel. The heater now dissipates a power the ration of power is

(a) 2: 1

(b) 1: 2

(c) 1: 4

(d) 4: 1

Q-31. Order of e/m ratio of proton, a-particle and electron is




(d) None of these

Q-32. A body is projected with zero velocity from the top of a tower and it reaches the ground in 4 sec. Calculate the distance travelled

(a) 80 m

(b) 90 m

(c) 160 m

(d) 40 m

Q-33. Ultraviolet rays are used in

(a) To detect scripture of old monuments

(b) Forensic labs

(c) Green house effect

(d) None of these

Q-34. A ray of light passing through the optic centre of a thick lens is

(a) Displaced and deviated

(b) Displaced but not deviated

(c) Not displaced and but deviated

(d) None of these

Q-35. According to Bohr՚s postulates which of the following quantities takes discrete values?

(a) Kinetic energy

(b) Potential energy

(c) Angular momentum

(d) Momentum

Q-36. An electron moves with uniform velocity and enters a region of uniform magnetic field B. If V and B are parallel to each other, then the electron will

(a) Continue to move in the same direction

(b) Move in a direction perpendicular to B

(c) Move in a circular path

(d) Will not move.

Q-37. The energy released per fission of a nucleus is nearly

(a) 200 eV

(b) 20 MeV

(c) 200 MeV

(d) 2000 eV

Q-38. Astigmatism can be corrected by using

(a) Biofocal lenses

(b) Concave spherical lenses

(c) Plane convex lenses

(d) Cylindrical lenses

Q-39. Astigmatism can be corrected by using

(a) Biofocal lenses

(b) Concave spherical lenses

(c) Plane convex lenses

(d) Cylindrical lenses

Q-40. Blue color of the sky is due to

(a) Scattering of light

(b) Dispersion of light

(c) Interference

(d) Sun emits more of blue light

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