Answer:
option A
Explanation:
given,
For exerted by the worker = 245 N
angle made with horizontal = 55°
we need to calculate Force which is not used to move the crate = ?
Movement of crate is due to the horizontal component of the force.
Crate will not move due to vertical force acting on the it.
hence, worker's force not used to move the crate is equal to 200.69
The correct answer is option A
Answer:
if the intensity of photons is constant then number of ejected electrons will remain same
Explanation:
As per photoelectric effect we know that when light of sufficient frequency fall on the surface of metal then electrons get ejected out of the surface with certain kinetic energy
Here the energy of photons is used to eject out the electrons from metal surface and to give the kinetic energy to the ejected electrons
so we have
here W = work function of metal which shows the energy required to eject out electrons from metal surface
KE = kinetic energy of ejected electrons
now if we increase the frequency of the photons that incident on the metal surface then in that case the incident energy will increase
So the electrons will eject out with more kinetic energy while if the number of photon is constant or the intensity of photons is constant then number of ejected electrons will remain same