The half-life of a substance is 2 years. After 6 years, what fraction of original substance remains? MCQ with Answer and Explanation

Question

Share Report Error

The half-life of a substance is 2 years. After 6 years, what fraction of original substance remains?

A. 1/8

B. 1/4

C. 1/16

D. 1/2

Answer: Option A

Solution (By JKExamLibrary)

3 half-lives => 1/8.

This question belongs to: Science Physics

Request complete Subject PDF

Discuss this Question (0)

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

Practice More Physics Questions

Question #1

Share Report

Resistance of wire: R = ρL/A. If length tripled and area doubled, new R is:

A. 1.5R

B. R/6

C. 3R

D. 6R

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option A

Explanation:
R' = ρ(3L)/(2A) = (3/2)(ρL/A) = 1.5R. Resistance scales directly with length, inversely with area. Memory aid: 'R ∝ L/A; changes multiply'. Proportional reasoning problem testing resistance formula, frequently appearing in competitive electricity sections.

This question belongs to: Science Physics

Question #2

Share Report

A convex lens is immersed in a liquid of same refractive index. Its focal length becomes

A. Same

B. Infinite

C. Half

D. Zero

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option B

Explanation:
Relative refractive index = 1, so lens behaves like glass slab, f infinite.

This question belongs to: Science Physics

Question #3

Share Report

The device used to measure the speed of a vehicle is

A. Odometer

B. Anemometer

C. Barometer

D. Speedometer

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option D

Explanation:
Speedometer measures instantaneous speed of vehicle. Odometer measures distance travelled. Anemometer wind speed. Barometer pressure.

This question belongs to: Science Physics

Explore All Physics MCQs