Question

A 50 volt AC is applied across an RC
(series) network. The rms voltage across
the resistance is 40 V, then the potential
across the capacitance will be
(A) 30 V
(B) 20 V
(C) 40 V
(D) 10 V​

Answer 1

Answer:

ans: C

Explanation:

BECAUSE IF AC IS 50, RESISTANCE IS 40, THEN IT IS 40

Answer 2

ANSWER:

20N

EXPLANATION:

Let the width of door is L,m then

We are given F1=10 N

r = width of door = L m

By using formula of torque we can write $\tau 1=r \mathbf{x} \mathrm{F} 1$

Putting values we get

$\tau 1=r \mathrm{x} \mathrm{F} 1=10 \mathrm{L}$

$\tau 1=10 L$

Now if the length is half then

$\tau 2=\frac{L}{2} \mathrm{xF} 2=\mathrm{F} 2\left(\frac{L}{2}\right)$

And if $\tau 1=\tau 2$ then

$10 \mathrm{L}=\mathrm{F} 2\left(\frac{L}{2}\right)$

Dividing by Lon both sides we get

10=F/2

F=20N

Thus we need the 20N force to open the door.