Solution :
We assume that there is a ring having a charge +Q and radius r. Electric field due to the ring at a point P on the axis is given by :




If we put an electron on point P, then force on point e is :

![F= \frac{-eKQx}{(r^2+x^2)^{3/2}}= \frac{-eKQx}{r^3[1+\frac{x^2}{r^2}]^{3/2}}](https://tex.z-dn.net/?f=F%3D%20%5Cfrac%7B-eKQx%7D%7B%28r%5E2%2Bx%5E2%29%5E%7B3%2F2%7D%7D%3D%20%5Cfrac%7B-eKQx%7D%7Br%5E3%5B1%2B%5Cfrac%7Bx%5E2%7D%7Br%5E2%7D%5D%5E%7B3%2F2%7D%7D)
If r >> x , then 
Then, 


Compare, a = -ω²x
We get,




A soft metal core made into a magnet by the passage of electric current through a coil surrounding it.
Answer:
Explanation: 100 watts is a unit of power.
A watt is also the amount of energy being consumed. So the more watts the brighter the light bulb is lit.
Answer:
Part a)
the tension force is equal to the weight of the crate
Part b)
tension force is more than the weight of the crate while accelerating upwards
tension force is less than the weight of crate if it is accelerating downwards
Explanation:
Part a)
When large crate is suspended at rest or moving with uniform speed then it is given as

here since speed is constant or it is at rest
so we will have


so the tension force is equal to the weight of the crate
Part b)
Now let say the crate is accelerating upwards
now we can say


so tension force is more than the weight of the crate
Now if the crate is accelerating downwards


so tension force is less than the weight of crate if it is accelerating downwards