Mercury is very harmful to the average human being. the mercury can easily be released from the lamp if the lamp is knocked over and broken. mercury is also harmful if inhaled. sodium on the other hand is not harmful in any way.
Explanation:
It is given that,
Force, 
Position vector, 
(a) The torque on the particle about the origin is given by :

(b) To find the angle between r and F use dot product formula as :

Hence, this is the required solution.
Hey user
The energy E in joules (J) is equal to the voltage V in volts (V), times the electrical charge Q in coulombs (C):
E(J) = V(V) ×<span> Q</span>(C)
So
joule = volt × coulomb
or
J = V × C
Example
What is the energy in joules that is consumed in an electrical circuit with voltage supply of 15V and charge flow of 4 coulombs?
E = 15V × 4C = 60J
The second option rolling friction