An electric kettle consumes $1\, kW$ of electric power when operated at $220\, V$. A fuse wire of what rating (in $A$) must be used for it?

$(a)$ State the commercial unit of electric energy and find its relation with its $SI$ unit.

$(b)$ The current through a resistor is made three times its initial value. Calculate how it will affect the heat produced in the resistor.

$(c)$ Find the increase in the amount of heat generated in a conductor if another conductor of double resistance is connected in the circuit keeping.all other factors unchanged.

State the formula co$-$relating the electric current flowing in a conductor and the voltage applied across it. Also, show this relationship by drawing a graph. What would be the resistance of a conductor, if the current flowing through it is $0.35$ ampere when the potential difference across it is $1.4$ volt ?

There are two electric bulbs, $(i)$ marked $60\, W$, $220\, V$ and $(ii)$ marked $100 \,W , 220 \,V .$ Which one of them has higher resistance ?

What is the resistance of an ideal ammeter ?

$(a)$ State $Ohm's$ law. Express it mathematically.

$(b)$ Write symbols used in electric circuits to represent

$(i)$ variable resistance.

$(ii)$ voltmeter.

$(c)$ An electric bulb is rated $220, V$ and $100\, W$ When it is operated on $110\, V ,$ what will be the power consumed ?