The answer is B, Law of Kinetic Energy
Answer:
y = 10.2 m
Explanation:
It is given that,
Charge, 
It is placed at a distance of 9 cm at x axis
Charge, 
It is placed at a distance of 16 cm at x axis
We need to find the point on the y-axis where the electric potential zero. The net potential on y-axis is equal to 0. So,

Here,

So,

Squaring both sides,

So, at a distance of 10.2 m on the y axis the electric potential equals 0.
Answer:
d = 1.55 * 10⁻⁶ m
Explanation:
To calculate the distance between the adjacent grooves of the CD, use the formula,
..........(1)
The fringe number, m = 1 since it is a first order maximum
The wavelength of the green laser pointer,
= 532 nm = 532 * 10⁻⁹ m
Distance between the central maximum and the first order maximum = 1.1 m
Distance between the screen and the CD = 3 m
= Angle between the incident light and the diffracted light
From the setup shown in the attachment, it is a right angled triangle in which


Putting all appropriate values into equation (1)

Answer:
r₂ = 0.2 m
Explanation:
given,
distance = 20 m
sound of average whisper = 30 dB
distance moved closer = ?
new frequency = 80 dB
using formula

I₀ = 10⁻¹² W/m²
now,



to hear the whisper sound = 80 dB



we know intensity of sound is inversely proportional to square of distances



r₂ = 0.2 m