NEET TEST SERIES 146 PHYSICS

1. A student measured the diameter of a small steel ball using a screw gauge of least count 0.001 cm. The main scale reading is 5 mm and the 25^th division of the circular scale coincides with the reference level of the main scale. If screw gauge has a zero error of -0.004 cm, the correct diameter of the ball is:

(a) 0.521 cm
(b) 0.529 cm
(c) 0.053 cm
(d) 0.525 cm

2. A simple pendulum of period T has a metal bob which is negatively charged. If it is allowed to oscillate above a positively charged metal plate, its period will:

(a) Remain equal to T
(b) Be less than T
(c) Be greater than T
(d) Be infinite

3. A specimen of silicon is to be made p-type semiconductor. For this one atom of indium, on an average, is doped in 5 X 10⁷ silicon atoms. If the number density of silicon is 5 X 10²⁸ atOms/m², then the number of acceptor atoms per cm³ will be:

(a)  2.5 × 10³⁰ 
(b) 1.0 ×10¹³
(c) 1.0 ×10¹⁵
(d) 2.5× 10³⁶

4. A person of mass 60 kg is inside a lift of mass 940 kg and presses the button on control panel. The lift starts moving upwards with acceleration 0 ms ^-2. If g = 1.0 ms ^-2, the tension in the supporting cable is:

(a) 8600 N
(b) 9680 N
(c) 11000 N
(d) 1200 N

5. At constant volume, temperature of a cylinder is increased then:

(a) Collision on walls will be less
(b) Collision frequency will increase
(c) Collision will be in straight line
(d) Collision will not change

6. A parallel beam of monochromatic light of wavelength 5000 Å is incident normally on a single narrow slit of width 0.001 mm. The light is focused by a convex lens on a screen placed on the focal plane. The first minima will be formed for the angle of diffraction equal to

(a) 0°
(b) 15°
(c) 30°
(d) 60°

7. The acceleration due to gravity on planet A is 9 times the acceleration due to gravity on planet B. A man jumps to a height of 2 m on the surface of planet A. What is the height of the same jump on planet B?

(a) 18 m
(b) 6 m
(c) 2/3 m
(d) 219 m

8. A particle is executing SHM along a straight line. Its velocities at distances x₁ and x₂  from the mean position are and respectively. Its time period is:

9. A polarizer is used to

(a) reduce intensity of light.
(b) produce polarized light.
(c) increase intensity of light.
(d) produce unpolarized light.

10. The wet-ability of a surface by a liquid depends primarily on:

(a) Density
(b) Angle of contact between surface and liquid
(c) Viscosity
(d) Surface tension

11. A small object of uniform density rolls up a curved surface with an initial velocity “v“. It reaches up to a maximum height of 3v²/ 4g with respect to the initial position. The object is:

(a) Solid sphere
(b) Hollow sphere
(c) Disc
(d) Ring

12. A physical quantity of the dimension of length that can be formed out of c, G and e²/4πε₀ is: [c is velocity of light, G is universal constant of gravitation, e is charge]

13. The oscillation of a body on a smooth horizontal surface is represented by the equation X = A cos (ωt), where X = displacement at time and t, and ω = frequency of bullet oscillation. Which one of the following graph shows correctly variation of  ‘a‘  with ‘t‘?

14. A plane polarised light coming out of a polarizer with intensity enters an analyser kept at an angle of 45° with the polarizer. What will be the intensity of the light coming out of the analyser?

15. Three sound waves of equal amplitudes have frequencies (n – 1) n, (n + 1). They superimpose to give beats. The of beats produced per second will be:

(a) 1
(b) 4
(c) 3
(d) 2

16. The isothermal elasticity of a gas is equal to:

(a) Density
(b) Volume
(c) Pressure
(d) Specific heat

17. If the dimensions of a physical quantity are given by [M^a L^b T^c], then the physical quantity will be:

(a) Force if, a = 0 b =-1, c = – 2
(b) Pressure if, a=1, b = – 1, c = -2
(c) Velocity if a = 1, b = 0 ,c= – 1
(d) Acceleration if, a = 1, b = 1 c = – 2

18. Liquid oxygen at 50 K is heated to 300 K at constant pressure of 1 atm. The rate of heating is constant. Which one of the following graphs represents the variation of temperature with time?

19. Velocity of light in glass whose refractive index with respect to air is 1.5 is 2 10⁸ m/s Also in certain unknown liquid the velocity of light is found to be 5 × 10⁸ m/s . The refractive index of the liquid with respect to air is

(a) 0.64
(b) 0.80
(c) 1.20
(d) 1.44

20. A semi-conducting device is connected in a series circuit with a resistance. A current is found to pass through the circuit. If the polarity of the battery is reversed, the current drops to almost zero. The device may be:

(a) A p-n junction
(b) An intrinsic semi-conductor
(c) A p-type semi-conductor
(d) An n-type semiconductor