Physics Questions: Paper - 9

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Sr. No.

Physics Model Question Paper 9: (For Class 11 and 12 and Pre-Medical/Engineering Entrance)

Answers

1.

Two protons are kept at a separation of 40 . Fn is the nuclear force and Fe is the electrostatic force between them. Then

(A) Fn >> Fe

(B) Fn = Fe

(C) Fn << Fe

(D) Fn Fe

Answer: (C)

2.

Two similar circular loops carry equal currents in the same direction. Un moving the coils further apart, the electric current will

(A) increase in both

(B) decrease in both

(C) remain unaltered

(D) increases in one and decreases in the second

Answer: (A)

3.

Two simple harmonic motions are represented by y1 = 5[Sin2pt + Cos2pt] and y2 = 5 sin . The ratio of their amplitude is _____.

(A) 1 : 3

(B) : 1

(C) 1 : 1

(D) 2 : 1

Answer: (D)

4.

Two slabs are of the thicknesses d1 and d2. Their thermal conductivities are K1 and K2 respectively. They are in series. The free ends of the combination of these two slabs are kept at temperatures q1 and q2. Assume q1 > q2. The temperature q of their common junction is ______.

(A)

(B)

(C)

(D)

Answer: (A)

5.

Two tangent galvanometers A and B are identical except in their number of turns. They are connected in series. On passing a current through them, deflections of 600 and 300 are produced. The ratio of the number of turns in A and B is

(A) 1 : 3

(B) 3 : 1

(C) 1 : 2

(D) 2 : 1

Answer: (B)

6.

Water is in streamline flow along a horizontal pipe with nonuniform cross-section. At a point in the pipe where the area of cross-section is 10 cm2, the velocity of water is 1 ms-1 and the pressure is 2000 Pa. The pressure at another point where the cross-sectional area is 5 cm2 is ______.

(A) 1000 Pa

(B) 500 Pa

(C) 4000 Pa

(D) 2000 Pa

Answer: (B)

7.

What is the minimum thickness of a thin film required for constructive interference in the reflected light from it?

Given, the refractive index of the film = 1.5, wavelength of the light incident on the film = 600 nm.

(A) 50 nm

(B) 200 nm

(C) 100 nm

(D) 300 nm

Answer: (C)

8.

When a neutron is disintegrated to give a b-particle, ______.

(A) a proton alone is emitted.

(B) a proton and an antineutrino are emitted.

(C) a neutrino alone is emitted.

(D) a proton and neutrino are emitted.

Answer: (B)

9.

When a piece of metal is illuminated by a monochromatic light of wavelengthl, then stopping potential is 3Vs. When same surface is illuminated by light of wavelength 2l, then stopping potential becomes. Vs. The value of threshold wavelength for photoelectric emission will be

(A) 4l

(B) 8l

(C)

(D) 6l

Answer: (A)

10.

Which of the following is a dichroic crystal?

(A) Quartz

(B) Tourmaline

(C) Mica

(D) Selenite

Answer: (B)