Assertion : `X` - rays can penetrate through the flesh but not through the bones.
Reason : The penetrating power of `X` - rays depends on voltage.

Options

A. If both assertion and reason are true and the reason is the correct explanation of the assertion.
B. If both assertion and reason are true but reason is not the correct explanation of the assertion.
C. If assertion is true but reason is false.
D. If the assertion and reason both are false.

Answer

B

Explanation

The penetrating power of X-rays depends upon the voltage applied across the tube producing X-rays. Xrays can pass through matter of lighter elements such as flesh (which is composed of oxygen, hydrogen and carbon) but cannot pass through substances made of heavier elements like bones (which are made of phosphorus and calcium).