Electrical Energy and Power — Prelims Questions

An electric heater is rated 1500 W, 220 V. If it operates for 2 hours, what is the electrical energy consumed in kilowatt-hours?

Two electric bulbs are rated (220V, 60W) and (220V, 100W) respectively. If they are connected in series across a 220V supply, which bulb will glow brighter?

A current of $2,\text{A}$ flows through a $5,Omega$ resistor for $10,\text{minutes}$. Calculate the heat produced in the resistor.

An electric motor of efficiency 80% draws a current of $5,\text{A}$ from a 220V supply. What is the useful mechanical power output of the motor?

A resistor of resistance $R$ dissipates power $P$ when a current $I$ flows through it. If the current is doubled, what will be the new power dissipated?

A 100W, 220V bulb is connected to a 110V supply. Assuming its resistance remains constant, what is the actual power consumed by the bulb?