Physics Model Question Paper | Welight CET

Physics Model Question Paper 1: (For Class 11 and 12 and Pre-Medical/Engineering Entrance)

1.

n₁ is the frequency of the series limit of Lyman series, n₂ is the frequency of the first line of Lyman series and n₃ is the frequency of the series limit of the Balmer series. Then ______.

(A) 

(B) 

(C) n₁ - n₂ = n₃

(D) n₁ = n₂ - n₃

Answer: (C)

2.

Two beams of red and violet colours are made to pass separately through a prism of A = 60°. In the minimum deviation position, the angle of refraction inside the prism will be

(A) greater for violet colour

(B) 30° for both the colours

(C) greater for red colour

(D) equal but not 30° for both the colours

Answer: (B)

3.

₉₂U²³⁵ undergoes successive disintegrations with the end product of ₈₂Pb²⁰³. The Number of a and bparticles emitted are

(A) a = 6, b = 4

(B) a = 6, b = 0

(C) a = 8, b = 6

(D) a = 3, b = 3

Answer: (C)

4.

A bat flies at a steady speed of 4 ms^-1 emitting a sound of f = 90 ´ 10³ Hz. It is flying horizontally towards a vertical wall. The frequency of the reflected sound as detected by the bat will be _____.

(Take velocity of sound in air as 330 ms^-1).

(A) 92.1 ´ 10³ Hz

(B) 89.1 ´ 10³ Hz

(C) 88.1 ´ 10³ Hz

(D) 87.1 ´ 10³ Hz

Answer: (A)

5.

A battery of e.m.f. E has an internal resistance 'r'. A variable resistance R is connected to the terminals of the battery. A current I is drawn from the battery. V is the terminal P.D. lf R alone is gradually reduced to zero, which of the following best describes I and V?

(A) I approaches E / r, V approaches E

(B) I approaches infinity, V approaches E

(C) I approaches zero, V approaches E

(D) I approaches E / r, V approaches zero

Answer: (D)

6.

A boat has green light of wavelength l = 500 nm on the mast. What wavelength would be measured and what colour would be observed for this light as seen by a diver submerged in water by the side of the boat? Given n_w = 4/3.

(A) Green of wavelength 500 nm

(B) Blue of wavelength 376 nm

(C) Green of wavelength 376 nm

(D) Red of wavelength 665 nm

Answer: (C)

7.

A body is projected vertically upwards. The times corresponding to height h while ascending and while descending are t₁ and t₂ respectively. Then the velocity of projection is (g is acceleration due to gravity)

(A) 

(B) 

(C) 

(D) 

Answer: (D)

8.

A body of mass 4 kg is accelerated upon by a constant force, travels a distance of 5 m in the first second and a distance of 2 m in the third second. The force acting on the body is

(A) 2 N

(B) 4 N

(C) 6N

(D) 8N

Answer: (C)

9.

A body weighs 50 grams in air and 40 grams in water. How much would it weigh in a liquid of specific gravity 1.5?

(A) 30 grams

(B) 35 grams

(C) 65 grams 

(D) 45 grams

Answer: (B)

10.

A capacitor and an inductance coil are connected in separate AC circuits with a bulb glowing in both the circuits. The bulb glows more brightly when ______.

(A) separation between the plates of the capacitor is increased.

(B) a dielectric is introduced into the gap between the plates of the capacitor.

(C) an iron rod is introduced into the inductance coil.

(D) the number of turns in the inductance coil is increased.

Answer: (B)

11.

A bar magnet is equivalent to _______.
(A) solenoid carrying current
(B) circular coil carrying current
(C) toroid carrying current
(D) straight conductor carrying current

Answer: (A)

12.

A beam of light of wavelength 600 nm from a distant source falls on a single slit 1mm wide and the resulting diffraction pattern is observed on a screen 2m away. The distance between the first dark fringes on either side of the central bright fringe is _______.
(A) 1.2 mm
(B) 1.2 cm
(C) 2.4 cm
(D) 2.4 mm

Answer: (D)

13.

A beam of parallel rays is brought to a focus by a plano-convex lens. A thin concave lens of the same focal length is joined to the first lens. The effect of this is _______.
(A) the focal point shifts away from the lens by a small distance.
(B) the focus remains undisturbed. T
(C) the focus shifts to infinity.
(D) the focal point shifts towards the lens by a small distance.

Answer: (C)

14.

A biconvex lens has a radius of curvature of magnitude 20 cm. Which one of the following options describe best the image formed of an object of height 2 cm placed 30 cm from the lens?
(A) Real, inverted, height = 1 cm
(B) Virtual, upright, height = 1 cm
(C) Virtual, upright, height = 0.5 cm
(D) Real, inverted, height = 4 cm

Answer: (D)

15.

A body of mass 5 kg is thrown vertically up with a kinetic energy of 490 J. The height at which the kinetic energy of the body becomes half of the original value is ______.
(A) 12.5 m
(B) 10 m
(C) 2.5 m
(D) 5 m

Answer: (D)