A photoelectric cell is an electronic device which is used to convert light energy into electric energy.The operation of this device is based on photoelectric effect.
Light of suitable frequency i.e greater or equal to threshold frequency will fall on the cathode maintained at negative potential.The electron emission will take place and these electrons are drifted towards the anode which is at positive potential.
Here,only those radiations will be capable of emitting electrons irrespective of surface barrier of metals whose energy is greater than the work function.
We know that the radiation having long wavelength has least energy as energy and wavelength are inversely proportional to each other.

Here h is the Planck's constant,c is the velocity of light.
Here we have been given red light and blue light.
In the visible spectrum of radiation, the red light has longer wavelength than all other colors of light.Hence blue light has more energy as it's wavelength is less as compared to red light.
Hence, the blue light will activate the most and red the least.
Answer:
3.964 s
Explanation:
Metric unit conversion:
1 miles = 1.6 km = 1600 m.
1 hour = 60 minutes = 3600 seconds
75 mph = 75 * 1600 / 3600 = 33.3 m/s
22.5 mph = 22.5 * 1600/3600 = 10 m/s
Let g = 9.81 m/s2
Friction is the product of coefficient and normal force, which equals to the gravity

The deceleration caused by friction is friction divided by mass according to Newton 2nd law.

So the time required to decelerate from 33.3 m/s to 10 m/s so the wheels don't slide, with the rate of 5.886 m/s2 is

<span>Despite the Quantum Mechanical Model treating the electron mathematically as a wave rather than fixed patterns, the Quantum Mechanical model best illustrates the Bohr model because both models of the atom assign specific energies to an electron.</span>
Answer:
2100 J
Explanation:
Parameters given:
Force acting on the object, F = 420 N
Distance moved by object, d = 5m
The change in kinetic energy of an object is equal to the work done by a force acting on the object:
W = F * d
∆KE = F * d
∆KE = 420 * 5
∆KE = 2100 J
Option (a) is correct.
Change in volume during the band concert might have been caused by the constructive and destructive interference of sound waves.
Interference is the process of redistribution of energy when two or more waves superimpose on each other.When two sound waves which are in phase superimpose on each other, constructive interference takes place. During constructive interference , the amplitude of resulting waves increases.Thus the loudness of sound increases.
When two sound waves which are out of phase superimpose on each other, destructive interference takes place. During destructive interference , the amplitude of resulting waves decreases.Thus the loudness of sound decreases.