A proton and an electron are placed in a uniform electric field :-The magnitude of the electric force acting on them will be equal.The electric force acting on them will be equal.The magnitude of their acceleration will be equal.Their acceleration will be equal.

The given statement seems to be a mix of different statements. Let's break it down:

1. "A proton and an electron are placed in a uniform electric field :-The magnitude of the electric force acting on them will be equal."

This is true. The electric force (F) acting on a charged particle in an electric field (E) is given by F = qE, where q is the charge of the particle. Since the magnitude of the charge of a proton and an electron is the same (but opposite in sign), the magnitude of the force acting on them will be equal.

2. "The electric force acting on them will be equal."

This is also true, but it's important to note that the direction of the force will be opposite. The electric force on a positive charge (like a proton) is in the direction of the electric field, while the force on a negative charge (like an electron) is in the opposite direction.

3. "The magnitude of their acceleration will be equal."

This is not true. The acceleration (a) of a particle under a force (F) is given by a = F/m, where m is the mass of the particle. Since the mass of a proton is much larger than the mass of an electron, the electron will experience a much larger acceleration than the proton.

4. "Their acceleration will be equal."

This is also not true, for the same reasons as above. The electron will experience a larger acceleration than the proton, and the directions of their accelerations will be opposite (because the directions of the forces on them are opposite).