Physics Questions: Paper - 7

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Sr. No.

Physics Model Question Paper 7: (For Class 11 and 12 and Pre-Medical/Engineering Entrance)

Answers

1.

The dimensions of 'resistance' are same as those of _____ where h is the Planck's constant, e is the charge.

(A)

(B)

(C)

(D)

Answer: (A)

2.

The efficiency of Carnot's heat engine is 0.5 when the temperature of the source is T1 and that of sink is T2. The efficiency of another Carnot's heat engine is also 0.5. The temperature of source and sink of the second engine are respectively _____.

(A) T1 + 5, T2 - 5

(B) T1 + 10, T2 - 10

(C) 2T1, 2T2

(D) 2T1,

Answer: (C)

3.

The equation of a simple harmonic wave is given by y = 6Sin 2p(2t - 0.1x), where x and y are in mm and t is in seconds. The phase difference between two particles 2 mm apart at any instant is

(A) 180

(B) 360

(C) 540

(D) 720

Answer: (D)

4.

The focal length of a plano convex lens is 'f' and its refractive index is 1.5. It is kept over a plane glass plate with its curved surface touching the glass plate. The gap between the lens and the glass plate is filled by a liquid. As a result, the effective focal length of the combination becomes 2f. Then the refractive index of the liquid is ______.

(A) 1.25

(B) 1.33

(C) 1.5

(D) 2

Answer: (A)

5.

The forbidden energy gap in Ge is 0.72 eV. Given, hc = 12400 eV - . The maximum wavelength of radiation that will generate an electron hole pair is ______.

(A) 17222

(B) 1722

(C) 172220

(D) 172.2

Answer: (A)

6.

The magnetic field at the centre of a circular current carrying conductor of radius r is Bc. The magnetic field on its axis at a distance r from the centre is Ba. The value of Bc : Ba will be

(A) 1 :

(B) 1 : 2

(C) 2 : 1

(D) : 1

Answer: (C)

7.

The masses of two radioactive substances are same and their half lives are 1 year and 2 years respectively. The ratio of their activities after 6 years will be

(A) 1 : 4

(B) 1 : 2

(C) 1 : 3

(D) 1 : 6

Answer: (A)

8.

The maximum kinetic energy of emitted electrons in a photoelectric effect does not

depend upon

(A) wavelength

(B) frequency

(C) intensity

(D) work function

Answer: (C)

9.

The maximum number of possible interference maxima when slit separation is equal to 4 times the wavelength of light used in a double slit experiment is

(A)

(B) 9

(C) 8

(D) 4

Answer: (B)

10.

The most stable particle in Baryon group is

(A) neutron

(B) omega - particle

(C) proton

(D) lamda - particle

Answer: (C)