To answer this question, we will simply use Coulomb's which is stated as follows:
F = k*q1*q2 / r^2 where:
F is the magnitude of the force between the two charges
k is a constant = 9.00 * 10^9 N.m^2/C^2
q1 = <span>+2.4 × 10–8 C
q2 = </span><span>+1.8 × 10–6 C
r is the distance between the two charges = </span><span>0.008 m
Substituting in the equation, we get:
F = (9*10^9)(2.4*10^-8)(1.8*10^-6) / (0.008)^2 = 6.075 which is approximately 6.1 Newtons
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Here is your answer

REASON :
Given,
t= 20 secs
F= 20 N
s (displacement)= 5m
Now,
Power= \frac{Work done}{time}
P= W/t ...... (i)
W= F×s×cos(theta)
W= 20×5 × 1 (theta is 0 degree; so cos0= 1)
W= 100 J
Hence,
P= 100/20 (from eq. i)
P= 5 watts
HOPE IT IS USEFUL
As per Gauss Law
Net flux through enclosed surface is

here through this hemisphere total flux will pass through two portions
1). from the curved surface
2). from flat circular base
so now we have

given that


now we have



Answer:
a and b.
Explanation:
In general types of wave
1. Transverse wave :
In these waves particle are vibrate perpendicular to motion of waves.
Ex : Electromagnetic wave , Radio wave .
2. Longitudinal wave :
In these waves particle are vibrate along the motion of waves.
Ex : Sound wave
Mechanical wave :
1 .These are transverse wave or Longitudinal wave or combination of them .
2.These waves required medium for propagation.
3. The particle are vibrate perpendicular to motion of waves.
So the option a and b are correct.