There are four springs stretched by the same mass. spring a stretches 25 cm. spring b stretches 10 cm. spring c stretches 100 cm. spring d stretches 1 cm.

which spring has the largest spring constant?

a

b

c

d

D (1cm)

Explanation:

Force constant (k) = Fs/ x

k = force constant

Fs = spring force

x = compression

Increase in the length of the spring leads to decrease in the force constant.

Note : the length of the spring was converted from cm-metre.

Explanation:

Given:

Charge = q

Electric field strength =

weight of the droplet = mg

The charge is suspended motionless. This is because the electric force on the charge is balanced by the weight of the droplet.

electric force on charged droplet,

This is balanced by the weight,

Equating the two: