Question

A pendulum bob of mass 80 mg and carrying charge of 3 x 10-B C is placed in an horizontal electric field. It comes to equilibrium position at an angle of 37 with the vertical. Calculate the intensity of electric field. (g=10m/s²) Plz answer this​

Answer 1

Answer:

Mass =80mg

Charge =2×10

−8

Coulomb

Electric field =20,000Vm

−1

Given, mass =80mg=8×10

−6

kg

charge =q=2×10

−8

C

Let T be the tension in string and θ is the angle if string with vertical.

In equilibrium

Tsinθ=qE⟶(1)

Tcosθ=mg⟶(2)

Divide (1) by (2) we get

tanθ=

mg

qE

⇒tanθ=

80×10

−6

×10

2×10

−8

×2×10

4

tanθ=0.5

θ=tan

−1

(0.5)

θ=27

0

Now,

tension, T=

sinθ

qE

=

sin27

0

2×10

−8

×2×10

4

=8.8×10

−4

V