Question

A bulb rated 12 V and 48W is connected to in series with 50 V and 60W are connected in series 100 V supply , find current flows through each bulb 
1. 0.25A,0.83 A
2. 1 A, 3A
3. 4A, 1.2A
4. 1.2 A, 1.8A

Answer 1

Correct Answer - Option 3 : 4A, 1.2A

CONCEPT: 

• Electrical power is defined as the rate at which energy is transferred in an electrical circuit or the product of voltage and current. 
• It is mathematically written as

⇒ P = VI

Where P = Power,V = Voltage, I = Current

CALCULATION: 

Given - P₁ = 48 W, V₁ = 12V, P₂ = 60W and V₂ = 50V

• The current through the first bulb is given by

⇒ P₁ = V₁I₁

\(⇒ I_{1} = \dfrac{P_{1}}{V_{1}} = \dfrac{48}{12} = 4A\)

• The current through the second bulb is given by

⇒ P₂ = V₂I₂

\(⇒ I_{2} = \frac{P_{2}}{V_{2}} = \frac{60}{50} = 1.2A\)

• The current through bulbs are I₁ = 4A and I₂ = 1.2A respectively. Hence, option 3 is the answer.