Monday, 18 March 2019

NDA PAST QUESTIONS ON PHYSICS 2017

1. An object 1 cm high placed on the axis 15 cm from a converging lens forms an image 30 cm from the lens. The size of the image is ___.
A. 0.5 cm 
B. 1.5 cm 
C. 3 cm 
D. 2 cm


2. A concave mirror forms a magnified and erect image only when the object is placed
A. at the centre of curvature
B. at the focus
C. between the focus and the pole of the mirror
D. beyond the radius of curvature

3. A thin lens is placed 50cm from an illuminated object. The image produced has a linear magnification of 1/4. Calculate the power of the lens in dioptres.
A. 2.5
B. 5.0 
C. 10.0
D. 25.0 D

4. Which of the following is true about an image formed by a divergent mirror? (I) the image is always virtual (II) the image is always erect (III) the image lies between pole and focus (IV) the image is never magnified (V) the focal length is negative
A. I and II 
B. all five 
C. I only 
D. I, II, III and IV

5. The angular dispersion of a prism depends on __.
A. the index of refraction only
B. the angle of incidence as well as the index of refraction
C. the angle of incidence only
D. the prism angle

6. A man standing between two parallel mirrors in a barber's shop will see the following numbers of his own image.
A. Eight 
B. Two 
C. Infinite 
D. Four.

7. Which of the following statements are correct? The sensitivity of a galvanometer which incorporates an optical lever arrangement may be increased by providing ___.
A.a large number of turns in the coil
B. a thinner suspension with a torsional
C. a special alloy permanent magnet which gives a high magnetic flux
D. all of the above

8. A concave lens of focal length 20cm forms an image 1/the size of the object. The object distance is __.
A. 100 cm
B. 100/cm
C. 60 cm
D. 60/cm

9. Which of the following electromagnetic waves has the shortest wavelength?
A. radio waves
B. X-rays
C. Infra-red
D. Ultra-violet

10. The speed of light in air is 3 x 10ms-1, if the refractive index of light from air-to-water is 4/3, then which of the following is the correct value of the speed of light in water?
A. 4. x 10ms-1
B. 2.25 x 10ms-1
C. 4/x 10ms-1
D. 2.25 x 10ms-1

11. Two capacitors, each of the capacitance 2μF are connected in parallel. If the p.d accross them is 120V, calculate the charge on each capacitor.
A. 6.0 x 10-5  C
B. 1.2 x 10-4 C
C. 2.4 x 10-4 C
D. 2.25 x 10-4 C

12. Which of the following properties is an advantage of a lead-acid accumulator over an alkaline accumulator?
A. Possesses low internal resistance
B. Can be recharged
C. Has a shorter life span
D. Possesses higher emf.

13. Six dry cells each of emf. 2.0V and internal resistance of 1.0Ω  are connected in parallel across a load of 3.0Ω
 A. 0.63A
B. 0.50A
C. 0.31A
D. 0.22A

14. Which of the following phenomenon can occur only with sound waves?
A. interference only
B. interference and diffraction
C. interference, diffraction and refraction
D. diffraction and refraction

15. If radio waves travel at aspeed of 3 x 10kms-1, then the wavelength of a radio wave of frequencey 1.5MHz is
A. 200 m
B. 1.0 m
C. 0.20 m
D. 450 m

16. If the alternating current through a capacitor of reactance 4.0Ω is (20coswt)mA, what is the voltage across the capacitor as a function of time?
A. (57coswt)mV 
B. (80coswt)mV
C. (5sinwt) mV 
D. (80sinwt)V

17. In a series LCR circuit, the voltages across the inductor and capacitor are 18V and 12V respectively. If the output of the alternating voltage source connected to this series LCR circuit is 10V, what is the voltage drop across the resistor?
A. 19.2V
B. 10V
C. 4V
D. 8V

18. In the circuit C=85 μF and L = 42 mH. To the nearest tenth of a Hz, what is the resonance frequency?
A. 84 Hz 
B. 4 Hz 
C. 76 Hz 
D. 840 Hz
19. The coil in an electric generator rotated at 60 Hz has 146 turns with a cross-sectional area of 1 x 10-2 m2. The magnetic field is 1.06 Tesla; what is the maximum voltage?
A. 0.03 V
B. 131 V 
C. 66 V 
D. 93 V

20. The circular loop in the figure has a radius of 2.1 cm and makes an angle of 27 degrees with a 2-T magnetic field. To the nearest tenth of an mWb, what is the flux through the loop?
A. 120 mWb
B. 240 mWb
C. 2.5 mWb
D. 2 mWh

21. The circuit shown at the left has a resistance of 16Ω and consumes 2.6 watts of power, the rod has a width of 1.25 m between the tracks and moves to the right at 3.5m/s. What is the strength of the magnetic field of the nearest hundredth of Tesla?
A. 1.5 V
B. 6.4 V
C. 0.59V
D. 1.6 x 10-11 V  

22. A lorry of mass 2000kg moving at 6km/h is brought to rest over a distance of 20m. Calculate the average breaking force.
A. 2500 N
B. 1000N
C. 1,500N
D. 500N

23. A ball of mass 5.0kg moving with a velocity og 10.0m/s collides with a 2.5kg ball moving in the opposite direction with a velocity of 8.0 m/s. After the collision, the balls ease and move in the same direction. Calculate the velocuty of the composite body.
A. 4.0 m/s
B. 6.5 m/s
C. 8.0 m/s
D. 9.0m/s

24.  Which of the following has the lowest internal resistance when new?
A. Leclanche cell 
B. Daniel cell
C. Accumulator 
D. Torch battery

25. Heat is supplied to a test tube containing 100g of ice at its melting point. The ice melts completely in 1 min. What is the power rating of the source of heat?
A. 336W 
B. 450W 
C. 560W 
D. 600W
(Latent heat of fusion of ice =336J)

26. An object is projected with a velocity of 80m/s at an angle of 30° to the horizontal. The maximum height reached is:
A. 20 m
B. 80 m
C. 160 m
D. 120 m

27. A car moves with a speed of 30ms-1, Calculate the distance travelled in 30s. 
A. 30 m
B. 60 m
C. 450 m
D. 900 m

28. A stone of mass 0.5 kg is droped from a height of 12m. Calculate its maximum kinetic energy. [ g=10ms-2  ]
A. 3.0 J
B. 6.0 J
C. 30. 0 J
D. 60.0 J

29. A machine of efficiency 80% is used to lift a box. If the effort applied by the machine is twice the weight of the box, calculate the velocity ratio of the machine.
A. 0.50
B. 0.63
C. 0.80
D. 1.60

30. A metal sheet of area 100cmwas heated through 70˚ C, Calculaye its new area if the linear expansivity of the metal is 0.000017K-1
A. 100.06 cm
B. 100.12 cm
C. 100.24 cm
D. 100.36 cm

31. A copper cube weights 0.25N in air, 0.17N when completely immersed in paraffin oil and 0.15N when completely immersed in water. The ratio of upthrust in oil to upthrust in water is
A. 3:5 
B. 4:5
C. 7:0
D. 13:10

32. A wheel and axle is used to raise a load of 500 N by the application of an effort of 250 N If the radii of the wheel and the axle are 0.4cm and 0.1cm respectively, the efficiency of the machine is
A. 20% 
B. 40% 
C. 50% 
D. 60%

33. Which of the following radiations emitted in radioactive decay has momentum, a fairly high penetrating power and is deflected by a magnet?
A. Alpha particle 
B. Beta particle
C. Gamma radiation 
D. X-radiation

34. Which of the following radiations emitted in radioactive decay has momentum, a fairly high penetrating power and is deflected by a magnet?
A. Alpha particle 
B. Beta particle
C. Gamma radiation 
D X-radiation

A plane wave is represented by the equation
, calculate the frequency.
A. 175 Hz
B. 100 Hz 
C. 200 Hz 
D. 628 Hz


36. A 10000 g mass attached to a spring performs a simple harmonic motion on a frictionless table. The force constant of the spring is 60 N/m. Calculate the period of oscillation
A. 2.57 s 
B. 1.81 s 
C. 18.1 s 
D. 1.82

37. A simple pendulum has a length of 2.5 m, calculate its period.
A. 2.24 s 
B. 22.4 s 
C. 3.1 s 
D. 3.25

38. The period of oscillation of a simple pendulum which makes 75 oscillations in one minute is ___.
A. 0.80 s 
B. 0.08 s 
C. 1.25 s 
D. 1.00 s

40. Calculate the energy stored in a 10.0μF capacitor charged to 500 V using a
A. 50
B. 5000
C. 1.25 J
D. 1250 J

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