CBSE 12th 2026 Compartment Physics Set-1 (55/S/1) Solutions

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CBSE 12th 2026 Compartment Physics Set-1 (55/S/1)
Solutions


SECTION A

Q.1. Two particles A and B of the same mass but having charges q
and 4q respectively, are accelerated from rest through different
potential differences VAand VB such that they attain the same kinetic
energies. The value of is: VA/VB

(A)1/ 4
(B)1/ 2
(c) 2
(D) 4




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Q.2. A coil of resistance 20 Ω and self-inductance 10 mH is connected
to an ac source of frequency 1000/π Hz. The phase difference
between current in the circuit and the source voltage is:

(A) 30°

(B) 60°

© 75°

(D) 45°

Solution. (D) 45°




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Q 3. Isotones are nuclides having :

(A) same number of neutrons but different number of protons

(B) same number of protons but different number of neutrons

(C) same number of protons and also same number of neutrons




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(D) different number of protons and also different number of
neutrons Solution. (A) same number of neutrons but different number
of protons

Isotones are nuclides that share the same number of neutrons but have
different numbers of protons.

Explanation:

● Isotones: Nuclides with the same number of neutrons but different
numbers of protons. For example, 24He^4_2\text{He}24 He (with 2
protons and 2 neutrons) and 36 Li^6_3\text{Li}36 Li (with 3 protons
and 3 neutrons) are isotones because they both have 2 neutrons.

Given this, the correct answer is:

(A) same number of neutrons but different number of protons

Q.4. A bulb is rated (100 W, 110 V). It is operated by a current of 1.0 A
supplied by a step down transformer. If the input voltage and
efficiency of the transformer are 220 V and 0.9 respectively, the input
current drawn from the mains is:

(A) ½ A

(B) 3/8 A

© 5/9 A

(D) 4/ 7 A

Solution. (A) ½ A




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