Answer:

Explanation:
P = Power = 50 kW
n = Number of photons per second
h = Planck's constant = 
= Frequency = 781 kHz
r = Distance at which the photon intensity is i = 1 photon/m²
Power is given by

Photon intensity is given by

The distance is 
The masses of the objects and how much distance there is between them
Answer:
(a) -472.305 J
(b) 1 m
Explanation:
(a)
Change in mechanical energy equals change in kinetic energy
Kinetic energy is given by
Initial kinetic energy is 
Since he finally comes to rest, final kinetic energy is zero because the final velocity is zero
Change in kinetic energy is given by final kinetic energy- initial kinetic energy hence
0-472.305 J=-472.305 J
(b)
From fundamental kinematic equation

Where v and u are final and initial velocities respectively, a is acceleration, s is distance
Making s the subject we obtain
but a=\mu g hence

I believe the answer is d
Answer:
Option (B)
Explanation:
Light is a form of electro-magnetic waves. This light wave has distinct range of wavelength that allows it to form different colors of light. This means that the color of the light produces depending on the amount of wavelength it comprises.
The visible light ranges from Violet to Red, and this is observed as different colors when each of these electromagnetic waves strikes our eyes at a certain angle. The violet light has the shortest wavelength of about 410 nm, where the red light has the highest wavelength of about 650 nm.
Thus, the correct answer is option (B).