Explanation:
Given that,
Wavelength of the photon,
Work function of the metal,
We need to find the maximum kinetic energy of the ejected electrons. It can be calculated using Einstein's photoelectric equation as :
or
So, the maximum kinetic energy of the ejected electrons is 3 ev. Hence, this is the required solution.
Answer:
a) If I increase the number of moving charged particles per cubic meter in a conductor, I will have to increase the cross sectional area of the conductor to get the same amount of current for the same electric field in the conductor.
FALSE
As we know that
so here if we increase the number of charge per unit volume then we need to decrease the area to get same amount of current through the wire.
b) The change in magnetic flux in a closed loop induces an EMF that opposes the change in magnetic flux.
TRUE
As per lenz law the direction of induced EMF is always opposite to the change in the flux due to which EMF is induced in the closed loop.
c) The magnetic force per unit length of two long, parallel, current-carrying conductors is repulsive if the currents are flowing in the opposite direction.
TRUE
When magnetic field of first wire will interact with other then it will exert force on it
so here the force will be on other wire such that the two wire will repel when current in the two wires is opposite in direction.
d) . The total magnetic flux through a closed surface is equal to μ0I enclosed
FALSE
magnetic flux is the number of field lines passing through a given area
So it is given as
Answer and Explanation:
with reference to Einstein's theory of special relativity, the speed of an electromagnetic radiation, here, laser will not change in any inertial frame or remains same irrespective of any change in inertial frame.
Therefore, the speed of light measured in both the cases, i.e., in astronaut's reference frame and spaceship's reference frame will be equal to the speed of light in vacuum, i.e., .
The laser gun's speed in astronaut's reference frame is the same as the speed of the spaceship as it mounted on it, i.e., the speed of the laser gun is 200 million m/s.
The laser gun's speed measured in spaceship's reference frame will be zero, as it is mounted on the spaceship and is stationary in the spaceship's reference frame.