An element X has atomic number 17 and mass number 35. Number of neutrons is MCQ with Answer and Explanation

An element X has atomic number 17 and mass number 35. Number of neutrons is
A. 52
B. 35
C. 17
D. 18
Answer: Option D
Solution (By JKSSB Mock Tests)
Neutrons = 35 - 17 = 18 (Chlorine).

Discuss this Question (0)

No comments yet. Be the first to start the discussion!

Practice More Physics Questions

Question #1
The kinetic energy of a body becomes four times its initial value. The new momentum will be:
A. Twice the initial
B. Four times the initial
C. Half the initial
D. Same as initial

Correct Answer: Option A


Explanation:
Kinetic energy KE = p²/(2m), where p is momentum. Thus p = √(2m·KE). If KE becomes 4 times, p_new = √(2m·4KE) = 2√(2m·KE) = 2p_initial. Hence momentum doubles. This relationship shows momentum scales with square root of kinetic energy for constant mass. Memory tip: p ∝ √KE when mass constant. This conceptual link between momentum and kinetic energy is frequently tested in competitive exams to assess depth of understanding beyond rote formula memorization. Always derive relationships when direct formulas aren't recalled.

This question belongs to: Science Physics
Question #2
The time period of a seconds pendulum is
A. 1 s
B. 2 s
C. 0.5 s
D. 4 s

Correct Answer: Option B


Explanation:
Seconds pendulum has period 2 s (1 s each swing).

This question belongs to: Science Physics
Question #3
A projectile is launched at 30° with speed 20 m/s. Horizontal range is: (g=10 m/s²)
A. 40 m
B. 20√3 m
C. 20 m
D. 10√3 m

Correct Answer: Option B


Explanation:
Range R = u²sin(2θ)/g = (20)²×sin(60°)/10 = 400×(√3/2)/10 = 20√3 m. Formula applies for level ground projection. Memory tip: sin(2θ) for θ=30° is sin60°=√3/2. Standard projectile calculation frequently appearing in competitive exams with trigonometric values.

This question belongs to: Science Physics