Question

In the circuit shown below, the battery voltage is 20 volts. What will be the reading of the ammeter shown in the circuit?

Answer 1

Series Combination

In such combination of resistors the current remains same but voltage differs.

Solution

$\bold{R_s = R_1 + R_2} \\ \\ \bold{R_s = 20 + 30 \:ohms} \\ \\ \bold{R_s = 50 \: Ohms}$

Since we know that,

R = V/i where R stands for resistance, V for voltage and i for current.

Therefore

50 = 20/i [Given : V = 20]

i = 20/50

i = 0.4 A

Here, symbol A stands for Ampere named after a scientist.

So current of 0.4 Ampere is drawn.

Answer : 0.4 Ampere

Answer 2

Solution :

The resistors in this circuit is in series combination. Potential difference across each resistance is different and is proportional to the resistance.

By using the formula of series combination of resistors.

Rs = R1 + R2

=> Rs = R1 + R2

=> Rs = 20 + 30

=> Rs = 50 Ohm

.°. Rs = 50 Ohm

Now,

By using the formula of Ohm's law.

R = V / I

Resistance is directly proportional to the potential difference and resistance is inversely proportional to the current.

For finding the current.

I = V / R

Current is directly proportional to the potential difference and current is inversely proportional to the resistance.

=> I = V / R

=> I = 20 / 50

=> I = 0.4 A

.°. I = 0.4 A

Answer : I = 0.4 A