Thursday, 7 March 2019

NDA PAST QUESTIONS ON PHYSICS 2013


1. The moment of inertia of an object does not depend upon __.
A. It’s mass
B. It’s size and shape
C. It’s angular velocity
D. the location of the axis of rotation

2. The minimum number of pulleys in a block and tackle needed to achieve an M.A of 6 is __.
A. 3
B. 4
C. 5
D. 6


3. A horizontal force of 150N is applied to a 51Kg carton on a level floor. The coefficient of static friction is 0.5 and that of sliding friction is 0.4. The frictional sliding force acting on the carton is? (g =9.8m/s
2)
A. 150 N
B. 200 N
C. 250 N
D. 500 N

4. An arrow bears a certain bow with a speed of 30m/s. What is its maximum range?
A. 90m
B. 25m
C. 30m
D. 3m

5. A lorry of mass 2000kg moving at 36km/h is brought to rest over a distance of 20m. Calculate the average breaking force
.
A. 2500 N
B. 10000 N
C. 15000 N
D. 5000 N

6. Which one of the following is not used for the detection of radiation?
A. Photographic emulsion
B. Cyclotron
C.
Spinthariscope
D. Cloud Chamber

7. The half-life of a radioactive isotope may be increased by ___.
A. increasing the mass present
B. increasing the illumination
C. raising the temperature
D. none of the above

8. Which one of the following statements is true?
A. the mass of a proton is about the same as that of an electron
the mass of an electron is about the same as that of a neutron
C. the mass of a proton is much greater than that of an electron
D. the mass of a neutron is much greatest than that of a
proton

9. Millikan's oil drop experiment was designed to calculate the ___.
A. charge on an electron
B. ratio of charge to mass of an electron
C, charge on an ion
D. ratio of charge to mass of an ion

10. A rate meter connected to a Geiger-Muller tube gives a count rate of 2000 per minute when a radioactive source is placed nearby. If the half of the source is 30 minutes, then after 2 hours the count rate would be ___.
A. 1000 per minute
B. 500 per minute
C. 250 per minute
D. 125 per minute

11. The charge on an electron is about ___.
A. 1,6 x 10
19 coulomb
B. 1.6 x 10
29 coulomb
C. 1.6 x 10
-19 coulomb
D. 1.6 x 10
29 coulomb

12. The apparent bending or a ruler when it is dipped into a beaker or water is due to ___.
A. reflection
B. refraction
C. diffraction
D. dispersion

13. If an object. is placed in front of a diverging lens, the image formed will be
A. real, on the same side of the lens as the object and diminished
B. virtual, on the same side of the lens as the object, and diminished
C. virtual, on the side of the lens as the object, and enlarged
D.  real, on the opposite side of the lens to the object and enlarged

14. An opaque object is floating 3.5cm above the bottom of a NO. but appears to be
floating 5.0cm below the surface. If the light is 10.0cm deep its refractive index is __.
A. 0.70
B. 0.78
C. 1.19
D. 1.30

15. A concave mirror of focal length 10cm forms an erect image. If the image is twice the size of the object, then the object
is at a distance from mirror of ___.
A. 3.3cm
B
. 5cm
C. 10cm
D. 15cm

16. If a radio waves travel at a speed of 3 x 10
5kms-1, then the wave length of a radio wave of frequency 1.5MHz is ___.
A. 0.20m
B. 5.0m
C. 200m
D. 450m

17. In Coulomb's Law, the force between two
-point charges is proportional to ___.
(i). the square of the distance between them
(ii). the product of the charges
(iii). the
permittivity of the medium
A. i and ii only
B. i and iii only
C. ii and iii only
D. ii only



18.  Fig 1
In Fig. l the potential at due to the charges at + Q and -Q is


19. The three capacitors in fig. 2 store a total energy in µ of __.
A. 12
B. 36
C. 48
D. 60

20. In Fig. 3(i) the time constant is 4s. The time constant in Fig.3(ii) is

A. 8
B. 4
C.
1/2
D. 1

21. An electrical heater supplies 320J in 1 minute to a 4Ω resistor. The steady current flowing in the resistor is about __.
A. 1.2A
B. 0.67A
C. 0.34A
D. 0.16A

22. The wire on a metre bridge is 100cm long. For the most accurate measurement of an unknown resistance, the balance point on the wire in cm should best be in the range of
A. 0 - 20
B. 20 - 40
C. 40 - 60
D. 60 - 80

23. A 50V D.C. motor has a coil of 0.la At 30 rev.min
-1 the current flowing is 5.0A. When the current flowing is less than 5.0A, the number of rev.min-1 is ___.
A. less than 30
B. more than 30
C. 30
D. 10

24. Tungsten obeys Ohms Law
because ___.
A. the wire becomes hot when current flows
B. the current is carried by electrons
C. the resistance is proportional to temperature
D. the current is proportional to p.d at constant temperature

25. When you sit in front of an open fire, you are warmed by ___.
A. Convection, Conduction and Radiation
B. Convection and Conduction
C. Radiation and Convection
D. Conduction only

26. Which of the following equations correctly relates a temperature F in degrees Fahrenheit and a corresponding temperature C in degree Celsius?
A. F = 9/5 x c + 32
B. F = 9/5 x c - 32
C. C = 915 x F + 32
D. C= 9/5 x F - 32

27. A 2m uniform conductor with resistivity P =2x 10
-1 m conducts a current
of 0. IA when connected across a 6v battery. that is the cross-sectional area A of the conductor?
A 6.7 x 10
-3 m
B. 0.67 x 10
-2 m
C. 6.7 10
-2 m
D. 0.67 x 10
-3 m

28. The specific latent heat of fusion of ice, is 340sk
g-1 when 10kg of water freezes
A. Absorbs 34KJof energy
B. Gives up to 34KJ of energy
C. Absorbs 3400KJof energy
D. Gives up 3400KJ of energy

29. A bimetallic strip bends when heated because the metals __.
A. have different temperature
B. expand in opposite directions
C. expand by different amounts
D. becomes softer when heated and the weight causes the strip to bend

30. Equal masses of Copper and Aluminium are to be placed in a beaker of water at 0°C. The Copper is initially at 50°c and the aluminium are 400Jkg
-1 k-1 and 880Jkg-1 k-1 respectively, the final water temperature will be __.
A. between 0°c and 50°c
B. between 50°c and 75°c
C. between 75°e and 100°c
D. Dependent upon the mass of water

31. On a sunny day, a driver parks his car with all the windows closed. When he returns
to the car, he finds it is unbearably hot inside. This is mainly because the infra-red rays from the sun ___.
A. pass through the windows and are absorbed by the seats which then emit long rays that cannot pass through the glass
B. are absorbed by the glass windows and the interior heats up by convection
C. pass through the windows but cannot escape because of total internal reflection
D. are focused into the interior by the windows which act as lenses

32. The melting point of naphthalene is 78°C. What is the temperature in Kelvin?
A. 100 K
B. 351 K
C. 378 K
D. 444 K

33. Which of the following is true of light and sound waves?
A. they both transmit energy
B. they both need a medium for propagation
C. they are both transverse eaves
D. their velocity in air are equal

34. When the bottom tip of a vibrating tuning fork is held in contact with a wooding box a louder sound is heard. This phenomenon is known as
___.
A. Beats
B. Echoing
C. Resonance
D. Reverberation

35. The current capacity of an accumulator is rued at 80 ampere-hours-(80
How long is such an accumulator expected to give a current of 20 ampere?
A. 2 hours
B. 3 hours
C. 4 hours
D. 5 hours

36. Which of the following normally produces a virtual
magnified image?
A. Camera
B. Binocular
C. Microscope
D. Cine-projector

37. A plane sound wave of frequency 85.5Hz and velocity 342 ms
1 is reflected from a nautical wall. At what distance from the wail does the wave have an anti-node
A. 4m
B. 2m
C. 1m
D. 3m

38. In a certain type of eye defect. the focal length of the cornea is different in various planes. Images in the planes are therefore focused at different points. What in this eye defect called?
A. Long sighted
B. Short sighted
C. Astigmatism
D. Homatism

39. What is the total change produced in a circuit when a current of 4A flows for 2 minutes?
A. 400 coulombs
B. 360 coulombs
C. 360 joules
D. 480 coulombs

40. The Leclanche cell contains a positive terminal made of carbon
: the negative terminal is made of what material?
A. Lead
B. Zinc
C. Electrode
D. Platinium

ANSWERS

1. B
2. D
3. D
4. A
5. B
6. B
7. D
8. A
9. A
10. D
11. C
12. B
13. B
14. D
15. B
16. C
17. D
18. A
19. C
20. A
21. A
22. C
23. B
24. D
25. C
26. A
27. A
28. D
29. C
30. D
31. A
32. B
33. B
34. C
35. C
36. A
37. A
38. C
39. D
40. B