Question

(a) which has more resistance :100w bulb or 60w bulb? (b)a wire of resistance 5w is bent in the fore of a closed circle. what effective resistance between the two points at the end of any diameter of the circle?

Answer 1

Answer:

hey mate.

Answer of A is:-

Assuming both bulbs are designed to operate at the same voltage V, then it's obvious that the higher the bulb's power rating P, the lower its resistance R, thus the 100W bulb has a lower resistance than the 60W bulb. 60W bulb has higher resistance than 100W bulb. ... 60 W bulb resistance = 60/230^2 = 0.00113 ohm

The answer of second question is:-

When a resistance is bent in a circle, the resistors are are connected in parallel.

Each of the resistors (the 2 parallel resistors of the circle) have a resistance of 10 ohms.

So we get the following-

Req = R1 x R2 / R1R2 (where Req is equivalent resistance in parallel connections)

OR

1/Rp =1/R1 + 1/R2 ( where Rp is resistance in parallel )

1/Rp = 1/10 + 1/10

1/Rp = 2/10

Rp = 10/2

Rp = 5 ohms

Explanation: