1.8 mol of Na. hope this helps
Answer:
The longest wavelength of light that is capable of ejecting electrons from that metal is 1292 nm.
Explanation:
Given that,
Wavelength = 400 nm
Energy 
We need to calculate the longest wavelength of light that is capable of ejecting electrons from that metal
Using formula of energy


Put the value into the formula



Hence, The longest wavelength of light that is capable of ejecting electrons from that metal is 1292 nm.
Answer:
Torque,
Explanation:
Given that,
The loop is positioned at an angle of 30 degrees.
Current in the loop, I = 0.5 A
The magnitude of the magnetic field is 0.300 T, B = 0.3 T
We need to find the net torque about the vertical axis of the current loop due to the interaction of the current with the magnetic field. We know that the torque is given by :

Let us assume that, 
is the angle between normal and the magnetic field, 
Torque is given by :

So, the net torque about the vertical axis is
. Hence, this is the required solution.
Answer:
This is because motion is intended to occur but at zero acceleration. It means at a constant velocity, henceFor that to happen the pulling force F must exactly equal the frictional force Fk .