Consider the statements.
1. Photon is a particle of light.
2. Mass of photon is not defined.
3. Speed of photon is as the speed of light.
4. Photons are charged.
Which options is/are correct?

. . . . . . . . invented Atom Bomb.

A. J Robert Oppenheimer

B. John Bau a Ning

C. Samuel Cohan

D. Samuel Colt

Positive rays were discovered by

A. Thomson

B. Goldstein

C. W-Crookes

D. Rutherford

Cathode rays are

A. positive rays

B. neutral rays

C. helium rays

D. electron waves

X-ray can be produced

A. when low speed electrons is ejected

B. when high speed electron is obstructed by a metal surface

C. when anode-ray obstructed by a solid object

D. when γ-ray is obstructed by a solid object