The answer to your problem is 15
Answer:
D.
For every action there is an equal and opposite reaction.
Explanation:
im doing the same one lol
Answer:
4589.05 year
Explanation:
The relation of activity is given by
we have given
Half life 
We know that half life 

So 



Answer:
q = 1.815 \times 10^{-8} C
Charge on one plate is positive in nature and on the other plate it is negative in nature.
Explanation:
E = 8.20 x 10^5 V/m, A = 25 cm^2, d = 22.45 mm
According to the Gauss's theorem in electrostatics
The electric field between the two plates




Charge, q = surface charge density x area

q = 1.815 \times 10^{-8} C
Answer : The correct option is, (d) 4 times
Solution :
According to the Coulomb's law, the electrostatic force of attraction or repulsion between two charges is directly proportional to the product of the charges and is inversely proportional to the square of the distance between the the charges.
Formula used :

where,
F = electrostatic force of attraction or repulsion
= Coulomb's constant
and
are the charges
r = distance between two charges
First we have to calculate the force exerted between S and q when the distance between the charge is 1 unit and let us assumed that the charge be 'q'
..........(1)
Now we have to calculate the force exerted between S and p when the distance between the charge is 2 unit at the same charge.
...........(2)
Equation equation 1 and 2, we get


Therefore, the force exerted between S and q is 4 times the force exerted between S and p.