Answer:

Explanation:
By Einstein's Equation of photoelectric effect we know that

here we know that
= energy of the photons incident on the metal
= minimum energy required to remove photons from metal
= kinetic energy of the electrons ejected out of the plate
now we know that it requires 351 nm wavelength of photons to just eject out the electrons
so we can say

here we know that

now we have

now by energy equation above when photon of 303 nm incident on the surface





Answer:
Redshift, or lower power
Explanation:
doppler effect
waves get stretched when you are moving away from something, and squished when you are moving towards it. Imagine you have a long, bent wire. if you stretch out the wire, the wavelength becomes longer. This also applies to sound.
Answer:
The particle path will follow
(d) a circular path
Explanation:
When a charged particle having charge of magnitude '
' enters into a magnetic field such that its velocity vector '
' is perpendicular to the direction of the magnetic field '
', then it will experience a force, called Lorentz force (
), given by

As shown in the figure, the magnetic field is directed perpendicular to the plane and towards the plane (as shown by the circle and 'X'-sign) and the velocity vector is from left to right on the plane.
According to the property of cross-product, the Lorentz force (
) acting on the particle will be perpendicular to the instantaneous position of the particle, making the path of the particle to be a circular path,as shown in the figure.