A piece of wire of resistance R is cut into five equal parts. These parts are then connected in parallel. If the equivalent resistance of this combination is R′, then the ratio R/R′ is _____.

a) 1/25

(b) 1/5

(c) 5

(d) 25

Asked by Vishal kumar | 1 year ago |  183

##### Solution :-

Explanation: The resistance is cut into five equal parts, which means that the resistance of each part is R/5. We know that each part is connected to each other in parallel, hence the equivalent resistance can be calculated as follows:

$$\frac{1}{R'}=\frac{5}{R}+\frac{5}{R}+\frac{5}{R}+\frac{5}{R}+\frac{5}{R}=\frac{5+5+5+5+5}{R}=\frac{25}{R}$$

$$\frac{R}{R'}=25$$

The ratio of $$\frac{R}{R'}$$is 25

Answered by Vishal kumar | 1 year ago

### Related Questions

#### Explain the following. a. Why is the tungsten used almost exclusively for filament of electric lamps?

Explain the following.

a. Why is the tungsten used almost exclusively for filament of electric lamps?

b. Why are the conductors of electric heating devices, such as bread-toasters and electric irons, made of an alloy rather than a pure metal?

c. Why is the series arrangement not used for domestic circuits?

d. How does the resistance of a wire vary with its area of cross-section?

e. Why copper and aluminum wires are usually employed for electricity transmission?

#### An electric heater of resistance 8 Ω draws 15 A from the service mains 2 hours. Calculate the rate at which heat is developed in the heater

An electric heater of resistance 8 Ω draws 15 A from the service mains 2 hours. Calculate the rate at which heat is developed in the heater.

#### Which uses more energy, a 250 W TV set in 1 hr, or a 1200 W toaster in 10 minutes?

Which uses more energy, a 250 W TV set in 1 hr, or a 1200 W toaster in 10 minutes?

#### Two lamps, one rated 100 W at 220 V, and the other 60 W at 220 V, are connected

Two lamps, one rated 100 W at 220 V, and the other 60 W at 220 V, are connected in parallel to the electric mains supply. What current is drawn from the line if the supply voltage is 220 V?