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Current Electricity

268378 An electric bulb is rated 220 volt and 100 watt. Power consumed by it when operated on 110 volt is

1 50 watt

2 75 watt

3 90 watt

4 25 watt

Explanation:

$P = \frac{V^{2}}{R}$

Current Electricity

268379 A heater coil is cut in to two parts of equal length and only one of them is used in the heater. Theratio of the heat produced by this half-coil to that by the original coil is

1

2 : 1

2

1 : 2

3

1 : 4

4

4 : 1

Explanation:

$W = J Q \Rightarrow Q = \frac{V^{2}}{R J} \Rightarrow \frac{Q_{1}}{Q_{2}} = \frac{R_{2}}{R_{1}}$

Current Electricity

268380 If the electric current in a lamp decreases by $5 %$ then the power output decreases by

1

20 %

2

10 %

3

5 %

4

2.5 %

Explanation:

$P = i^{2} R \Rightarrow P α i^{2} \Rightarrow \frac{Δ P}{P} \times 100 = 2 \times \frac{Δ I}{I} \times 100$

Current Electricity

268381 Two electric bulbs whose resistances are in the ratio of $1 : 2$ are connected in parallel to a constant voltage source. The powers dissipated in them have the ratio

1

1 : 2

2

1 : 1

3

2 : 1

4

1 : 4

Explanation:

$P = \frac{V^{2}}{R}$

Current Electricity

268378 An electric bulb is rated 220 volt and 100 watt. Power consumed by it when operated on 110 volt is

1 50 watt

2 75 watt

3 90 watt

4 25 watt

Explanation:

$P = \frac{V^{2}}{R}$

Current Electricity

268379 A heater coil is cut in to two parts of equal length and only one of them is used in the heater. Theratio of the heat produced by this half-coil to that by the original coil is

1

2 : 1

2

1 : 2

3

1 : 4

4

4 : 1

Explanation:

$W = J Q \Rightarrow Q = \frac{V^{2}}{R J} \Rightarrow \frac{Q_{1}}{Q_{2}} = \frac{R_{2}}{R_{1}}$

Current Electricity

268380 If the electric current in a lamp decreases by $5 %$ then the power output decreases by

1

20 %

2

10 %

3

5 %

4

2.5 %

Explanation:

$P = i^{2} R \Rightarrow P α i^{2} \Rightarrow \frac{Δ P}{P} \times 100 = 2 \times \frac{Δ I}{I} \times 100$

Current Electricity

268381 Two electric bulbs whose resistances are in the ratio of $1 : 2$ are connected in parallel to a constant voltage source. The powers dissipated in them have the ratio

1

1 : 2

2

1 : 1

3

2 : 1

4

1 : 4

Explanation:

$P = \frac{V^{2}}{R}$

Current Electricity

268378 An electric bulb is rated 220 volt and 100 watt. Power consumed by it when operated on 110 volt is

1 50 watt

2 75 watt

3 90 watt

4 25 watt

Explanation:

$P = \frac{V^{2}}{R}$

Current Electricity

268379 A heater coil is cut in to two parts of equal length and only one of them is used in the heater. Theratio of the heat produced by this half-coil to that by the original coil is

1

2 : 1

2

1 : 2

3

1 : 4

4

4 : 1

Explanation:

$W = J Q \Rightarrow Q = \frac{V^{2}}{R J} \Rightarrow \frac{Q_{1}}{Q_{2}} = \frac{R_{2}}{R_{1}}$

Current Electricity

268380 If the electric current in a lamp decreases by $5 %$ then the power output decreases by

1

20 %

2

10 %

3

5 %

4

2.5 %

Explanation:

$P = i^{2} R \Rightarrow P α i^{2} \Rightarrow \frac{Δ P}{P} \times 100 = 2 \times \frac{Δ I}{I} \times 100$

Current Electricity

268381 Two electric bulbs whose resistances are in the ratio of $1 : 2$ are connected in parallel to a constant voltage source. The powers dissipated in them have the ratio

1

1 : 2

2

1 : 1

3

2 : 1

4

1 : 4

Explanation:

$P = \frac{V^{2}}{R}$

Current Electricity

268378 An electric bulb is rated 220 volt and 100 watt. Power consumed by it when operated on 110 volt is

1 50 watt

2 75 watt

3 90 watt

4 25 watt

Explanation:

$P = \frac{V^{2}}{R}$

Current Electricity

268379 A heater coil is cut in to two parts of equal length and only one of them is used in the heater. Theratio of the heat produced by this half-coil to that by the original coil is

1

2 : 1

2

1 : 2

3

1 : 4

4

4 : 1

Explanation:

$W = J Q \Rightarrow Q = \frac{V^{2}}{R J} \Rightarrow \frac{Q_{1}}{Q_{2}} = \frac{R_{2}}{R_{1}}$

Current Electricity

268380 If the electric current in a lamp decreases by $5 %$ then the power output decreases by

1

20 %

2

10 %

3

5 %

4

2.5 %

Explanation:

$P = i^{2} R \Rightarrow P α i^{2} \Rightarrow \frac{Δ P}{P} \times 100 = 2 \times \frac{Δ I}{I} \times 100$

Current Electricity

268381 Two electric bulbs whose resistances are in the ratio of $1 : 2$ are connected in parallel to a constant voltage source. The powers dissipated in them have the ratio

1

1 : 2

2

1 : 1

3

2 : 1

4

1 : 4

Explanation:

$P = \frac{V^{2}}{R}$

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