Question

A small metallic ball is suspended in a uniform electric field with the help of an insulated thread. If a high energy X-ray beam falls on the ball, the ball will be deflected in the direction of the field.
A. True
B. False

Answer 1

Hint: Refer to the phenomenon of photoelectric effect. On removal of electrons from the metallic surface, the metallic surface becomes positively charged. Determine the force experienced by the charged metallic ball placed in a uniform electric field.

Complete step by step answer:
According to the photoelectric effect, when the high energy beam of photons falls on a metallic surface, the electrons from the metallic surface are emitted. Due to the emission of electrons from the metallic surface, the metallic surface gets positively charged.
If we place a positive charge in the uniform electric field, the charge experiences an electric force which moves it in the direction of the field. Also, if we place a negative charge in the uniform electric field, the charge moves in the opposite direction of the field.
A metallic ball is initially uncharged because of the same number of positive and negative charges in it. When the high energy X-ray beam falls on the metallic ball, it emits the electrons off the metallic ball. Therefore, the metallic ball becomes positively charged due to removal of negative charges.
As we discussed above, the positive charges move along the direction of the electric field. Therefore, the metallic ball will be deflected in the direction of the field.

So, the correct answer is “Option A”.

Note:
The removal of negative charges from an object makes the object more positively charged and not negatively charged.
The electrons are negatively charged.