The nucleus of an atom consists of MCQ with Answer and Explanation

The nucleus of an atom consists of
A. Electrons and neutrons
B. Only protons
C. Protons and neutrons
D. Electrons and protons
Answer: Option C
Solution (By JKExamLibrary)
Nucleus contains protons (positive) and neutrons (neutral), collectively nucleons. Electrons orbit nucleus. Atomic number Z = protons, mass number A = protons + neutrons. Isotopes differ in neutron number.

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Practice More Physics Questions

Question #1
A force of 10 N acts on a body of mass 2 kg for 1 s. Change in momentum is
A. 2 kg m/s
B. 10 kg m/s
C. 20 kg m/s
D. 5 kg m/s

Correct Answer: Option B


Explanation:
Impulse = F t = 10 N s = change in momentum.

This question belongs to: Science Physics
Question #2
A body starts from rest and moves with uniform acceleration a. The ratio of distances covered in the 1st, 2nd, and 3rd seconds of motion is:
A. 1:1:1
B. 1:2:3
C. 1:4:9
D. 1:3:5

Correct Answer: Option D


Explanation:
Distance covered in nth second: sₙ = u + a(2n-1)/2. With u=0, sₙ ∝ (2n-1). For n=1: 2(1)-1=1; n=2: 3; n=3:5. Thus ratio 1:3:5. This result holds for any uniformly accelerated motion starting from rest. The distances covered in successive equal time intervals follow odd number ratio. Memory aid: This is a standard result derivable from s = ut + ½at² by calculating s at t=n and t=n-1. Frequently appears in competitive exams testing equation of motion applications.

This question belongs to: Science Physics
Question #3
Gravitational force between two masses varies with distance r as:
A. 1/r
B.
C. r
D. 1/r²

Correct Answer: Option D


Explanation:
Newton's law: F = Gm₁m₂/r² ⇒ F ∝ 1/r². Inverse square law fundamental to gravitation, electrostatics, and radiation intensity. Memory aid: 'Gravity weakens with square of distance; double distance ⇒ force becomes 1/4'. Core concept frequently tested to verify understanding of fundamental force laws in competitive exams.

This question belongs to: Science Physics