Question

Q13 When a 40V battery is connected across an unknown resistor there is a current of 100 mA

in the circuit. Find the value of the resistance of the resister:

(a) 5000 Ω

(b) 800 Ω

(c) 0.8 Ω

(d) None of these
​

Answer 1

★Given :-

• Potential difference across the resistor = 40 V
• Current flowing = 100 m A = 100 × 0.001 = 0.1 A

★ To find :-

• Resistance

★ Solution :-

We can solve this question easily by using ohm's law

According to ohm's law ,

➽ V = I R

On rearranging ,

➸ R = V / I

➸ R = 40 / 0.1

➸ R. = 400 Ω

The value of resistance of the resistor is 400 Ω

★ Know more :-

➠ Series Combination :-

• When n number of resistors are connected in Series with each other then the equivalent resistance is given by the formula

$\bigstar\boxed{\mathtt{R_s = R_1 + R_2 ..... + R_n }}$

• In series combination current across all the resistors is the same

➠ Parallel Combination :-

• When n number of resistors are connected in parallel with each other then the equivalent resistance is given by the formula

$\bigstar\boxed{\mathtt{\dfrac{1}{R_p} = \dfrac{1}{R_1} +\dfrac{1}{R_2} .. . + \dfrac{1}{R_n} }}$

• In parallel combination the potential difference across the resistor is the same