Question

The value of universal gravitational constant was first determined by

• A. Newton
• B. Cavendish
• C. Einstein
• D. Galileo

Hint:

Cavendish experiment is also called “weighing the Earth” experiment.

Answer 1

The Correct Option is B

Step 1: Understand gravitational constant.
The universal gravitational constant \( G \) appears in Newton’s law of gravitation.

Step 2: Newton’s contribution.
Newton proposed the law of gravitation but did not measure \( G \).

Step 3: Cavendish experiment.
Henry Cavendish performed the torsion balance experiment to measure \( G \).

Step 4: Principle used.
He measured very small gravitational attraction between known masses.

Step 5: Calculation of \( G \).
From measured force and known masses and distance, he calculated \( G \).

Step 6: Historical significance.
This was the first experimental determination of gravitational constant.

Step 7: Final Answer.
\[ \boxed{\text{Cavendish}} \]