NEET TEST SERIES 87 PHYSICS -

Name

1. In a semiconductor

a) there are no free electrons at 0 K
b) there are no free electrons at any temperature
c) the number of free electrons increases with pressure
d) the number of free electrons is more than that in a conductorDeselect Answer

None

2. Of the diodes shown in the following diagrams, which one is reverse biased ?

A) (a)
B) (b)
C) (c)
D) (d)Deselect Answer

None

3. In the following circuit, the output Y for all possible inputs A and B is expressed by the truth table.

A) (a)
B) (b)
C) (c)
D) (d)Deselect Answer

None

4. In the combination of the following gates the output Y can be written in terms of inputs A and B as

Deselect Answer

None

5. Which process will increase the temperature of the system without heating it?

a) Adiabatic compression
b) Adiabatic expansion
c) Isothermal compression
d) Isothermal expansionDeselect Answer

None

6. A body has its centre of mass at the origin. The x-coordinates to the particles

a) May be all positive
b) May be all negative
c) Maybe positive for same case and negative for the other cases
d) Always zeroDeselect Answer

None

7. A particle of mass 200g is dropped from a height of 50m and another particle of mass 100g is simultaneously projected up from the ground along the same line, with speed of 100 m/s, the acceleration of the centre of mass after 1 sec will be

a) 10 m/s²b) 70/3 m/s

c) -70/3 m/s

d) 0

Deselect Answer

None

8. A solid cylinder of mass 2 kg and radius 4 cm rotating about its axis at the rate of 3 rpm. The torque required to stop after 2π revolutions is

a) 2 x 10⁶Nm
b) 2 x 10^-6Nm
c) 2 x 10^-3Nm
d) 12 x 10^-4Nm

Deselect Answer

None

9. Initially two stable particles x and y start moving towards each other under mutual attraction. If at one time the velocities of x and y are V and 2V respectively, what will be the velocity of centre of mass of the system?

Deselect Answer

None

10. The grinding stone of a flour mill is rotating at 600 rad/sec for the power of 1.2 K watt is used, the effective torque on stone N-m will be

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

Deselect Answer

None

11. The instantaneous angular position of a point on a rotating wheel is given by the equation θ (t)= 2t³-6t². The torque on the wheel becomes 0 at

a) t= 1s
b) t= 0.5s
c) t= 0.25s
d) t= 2s

Deselect Answer

None

12. A load of 10 kg is suspended by a metal wire 3 m long and having a cross-sectional area 4mm². Find the elongation in length. Young modulus of the metal is 2.0×1011Nm⁻²a) 2.75 x 10^-4m
b) 3.75 x 10^-4m
c) 4.75 x 10^-4m
d) 5.75 x 10^-4m

Deselect Answer

None

13. A force of 2 mm is applied to a steel wire with a length of 5 m and a cross-sectional area of 4 mm³. When steel has a Young’s modulus of 2×1011 N/m², the energy found within the wire equals

a) 0.64 J
b) 0.12 J
c) 0.28 J
d) 0.32 J

Deselect Answer

None

14. Four bodies A, B, C and D are projected with equal velocities having angles of projection 15°,30°,45°and 80° with the horizontal respectively. The body having the shortest range is

a) A
b) B
c) C
d) D

Deselect Answer

None

a) 2J
b) 5J
c) 18J
d) 11JDeselect Answer

None

16. A ray of light travelling in a medium of refractive index μ is incident at an angle θ on a composite transparent plate consisting of 50 plates of R.I1.01μ,1.02μ,1.03μ………,1.50μ . The ray emerges from the composite plate into a medium of refractive index 1.6μ at angle ‘x’ . Then :

Deselect Answer

None

17. A ray of light, travelling in a medium of refractive index mu, is incident at an angle i on a composite transparent plate consisting of three plates of refractive indices μ1, μ2 and μ3. The ray emerges from the composite plate into a medium of refractive index μ4, at angle x. Then,

Deselect Answer

None

18. The size of the image of an object, which is at infinity, as formed by a convex lens of focal length 30 cm is 2 cm. If a concave lens of focal length 20 cm is placed between the convex lens and the image at a distance of 26 cm from the convex lens, calculate the new size of the image

Deselect Answer

None

19. A concave shaving mirror has a radius of curvature of 35.0cm. It is positioned so that the (upright) image of man’s face is 2.50 times the size of the face. How far is the mirror from the face?

a) 5.25cm
b) 21.0cm
c) 10.5cm
d) 42cm

Deselect Answer

None

20. A ray incident at a point at an angle of incidence of 60∘enters a glass sphere with refractive index √3 and it is reflected and refracted at the farther surface of the sphere. The angle between the reflected and refracted rays at this surface is:

a) 50°
b) 60°
c) 90°
d) 40°

Deselect Answer

None

NEET TEST SERIES 87 PHYSICS

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