Electrical Energy and Electrical Power

An electric bulb marked $25 \mathrm{W}$ and $100 \mathrm{V}$ is connected across $50 \mathrm{V}$ supply. Now its power is

For the circuit show, all wires have negligible resistance, the battery has a constant internal resistance of $r=8.0\Omega$ and the two light bulbs $\left(B_1\right.$ and $\left.B_2\right)$ are identical, each with resistance $R_{bulb }$. The variable resistor is initially set $R=26.0\Omega$. The switch $S$ in the circuit now is closed. To what resistance must the variable resistor be set if bulb $B_1$ is to have the same brightness after the switch is closed as it did with the switch open?

Two bulbs $25 \mathrm{W}-220 \mathrm{V}$ and $100 \mathrm{W}-220 \mathrm{V}$ are given. Which has higher resistance?

A heater is designed in such a way that it uses $500 \mathrm{W}$ when connected to a $115 \mathrm{V}$ supply. If the line voltage drops to $110 \mathrm{V}$, the percentage drop in heat output will be

What should be the $emf$ applied across $A \text{and} B$ so that the magnitude of current crossing point $P$ becomes ${\frac{1}{10}}^{th}$ of the magnitude of power generated across the largest resistor of the network?

A wind generator provides power to a factory whose equipment operates at $120 \text{KW}$ and $240 \mathrm{V}$. The factory is connected to a wind generator with cables of total resistance of $0.80 \mathrm{\Omega }$.

It is suggested that a transformer be used to step up the voltage of the wind generator so that the step-down transformer near the factory would bring the voltage down from $2.4 \mathrm{KV}$ to $240 \mathrm{V}$.

Determine the power loss in the cables now. 

A wind generator provides power to a factory whose equipment operates at $120 \text{KW}$ and $240 \mathrm{V}$. The factory is connected to a wind generator with cables of total resistance of $0.80 \mathrm{\Omega }$.

Calculate the efficiency of the transmission system.

A wind generator provides power to a factory whose equipment operates at $120 \text{KW}$ and $240 \mathrm{V}$. The factory is connected to a wind generator with cables of total resistance of $0.80 \mathrm{\Omega }$.

Calculate the voltage at the wind generator.

A wind generator provides power to a factory whose equipment operates at $120 \text{KW}$ and $240 \mathrm{V}$. The factory is connected to a wind generator with cables of total resistance of $0.80 \mathrm{\Omega }$.

Calculate the power lost in the cables.

A wind generator provides power to a factory whose equipment operates at $120 \text{KW}$ and $240 \mathrm{V}$. The factory is connected to a wind generator with cables of total resistance of $0.80 \mathrm{\Omega }$.

It is suggested that a transformer be used to step up the voltage of the wind generator so that the step-down transformer near the factory would bring the voltage down from $2.4 \mathrm{KV}$ to $240 \mathrm{V}$.

Determine the power loss in the cables now. 

A wind generator provides power to a factory whose equipment operates at $120 \text{KW}$ and $240 \mathrm{V}$. The factory is connected to a wind generator with cables of total resistance of $0.80 \mathrm{\Omega }$.

Calculate the efficiency of the transmission line.

A wind generator provides power to a factory whose equipment operates at $120 \text{KW}$ and $240 \mathrm{V}$. The factory is connected to a wind generator with cables of total resistance of $0.80 \mathrm{\Omega }$.

Calculate the voltage at wind generator.

A wind generator provides power to a factory whose equipment operates at $120 \text{KW}$ and $240 \mathrm{V}$. The factory is connected to a wind generator with cables of total resistance of $0.80 \mathrm{\Omega }$.

Calculate the power lost in the cables.

An electric iron of $750 \mathrm{W}$ Power is connected to a $220 \mathrm{V}$ Mains. The current drawn by the iron is nearly.

In Joules's heating law, when $R$, and $t$, are constant. If $H$, is taken along the $y$, axis and $I^2$,along $x$,axis. The graph is

Two heating wires of equal length are first connected in series and then in parallel. If the combinations are separately connected across the same time. The ratio of heat produced in the first case to that on the second is. 

Three equal resistors connected in series with a source of emf together dissipate $10 \mathrm{W}$ of power. The power dissipated by these resistors connected in parallel will be

Of the two bulbs used in a house one glows more brightly than the other. Then which of the following statements is true ?

An electric iron of $750 \mathrm{W}$ Power is connected to a $220 \mathrm{V}$ Mains. The current drawn by the iron is nearly.

Three equal resistors connected in series with a source of emf to-gather dissipate $10 \mathrm{W}$ of power. The power dissipated by these resistors connected in parallel will be