If a proton and electron have same de broglie wavelength, then(A) Momentum of electron = momentum of proton(B) Velocity of electron > velocity of proton(C) Momentum of electron > momentum of proton(D) a and b both are correct

The de Broglie wavelength of a particle is given by the equation:

λ = h / p

where λ is the de Broglie wavelength, h is the Planck constant, and p is the momentum of the particle.

If a proton and an electron have the same de Broglie wavelength, it means their momenta are equal. This is because the wavelength is inversely proportional to the momentum. Therefore, option (A) is correct: the momentum of the electron is equal to the momentum of the proton.

However, we cannot determine the velocity of the particles solely based on their de Broglie wavelengths. The velocity of a particle depends on its mass and momentum. Since the mass of an electron is much smaller than the mass of a proton, their velocities will be significantly different even if their momenta are the same.

Therefore, option (B) is incorrect: we cannot conclude that the velocity of the electron is greater than the velocity of the proton. Option (C) is also incorrect because we have established that the momenta are equal.

Hence, the correct answer is option (A).