A) d. 10T
When a charged particle moves at right angle to a uniform magnetic field, it experiences a force whose magnitude os given by

where q is the charge of the particle, v is the velocity, B is the strength of the magnetic field.
This force acts as a centripetal force, keeping the particle in a circular motion - so we can write

which can be rewritten as

The velocity can be rewritten as the ratio between the lenght of the circumference and the period of revolution (T):

So, we get:

We see that this the period of revolution is directly proportional to the mass of the particle: therefore, if the second particle is 10 times as massive, then its period will be 10 times longer.
B) 
The frequency of revolution of a particle in uniform circular motion is

where
f is the frequency
T is the period
We see that the frequency is inversely proportional to the period. Therefore, if the period of the more massive particle is 10 times that of the smaller particle:
T' = 10 T
Then its frequency of revolution will be:

Answer:

Explanation:
Given that,
The wavelength of light, 
We need to find the frequency of the light. We know that,

So, the required frequency of light is equal to
.
The momentum change of the running back is - 664.2 kg m/s or 664 west.
<u>Explanation:</u>
Momentum is defined as the change in velocity of any object along with its mass. So mathematically, momentum can be derived using the product of mass with the change in velocity.

As here mass is given as 82 kg and the initial velocity was 5.6 m/s and final velocity is 2.5 m/s.
Initial Momentum = 
Final Momentum = 
Momentum change = Final Momentum - Initial Momentum
Momentum change = - 205 - 459.2 = - 664.2 kg m/s or 664 west
Thus, the changing momentum is -664.2 kg m/s. The negative sign indicates that the momentum is acting in the opposite direction on changing in the direction of velocity.