Compute the heat generated while transferring $96000$ coulomb of charge in one hour through a potential difference of $50\, V$.

Two lamps,one rated $100\, W$ at $220\, V$,and the other $60\, W$ at $220\, V$,are connected in parallel to electric mains supply. What current (in $A$) is drawn from the line if the supply voltage is $220\, V$?

An electric iron of resistance $20\, \Omega$ takes a current of $5\, A$. Calculate the heat developed in $30\, s$.

An electric heater of resistance $8 \, \Omega$ draws $15 \, A$ from the service mains for $2$ hours. Calculate the rate at which heat is developed in the heater (in $W$).

Explain the following.
$(a)$ Why is tungsten used almost exclusively for the filament of electric lamps?
$(b)$ Why are the conductors of electric heating devices,such as bread-toasters and electric irons,made of an alloy rather than a pure metal?

Show how you would connect three resistors,each of resistance $6 \, \Omega$,so that the combination has a resistance of $(i)$ $9 \, \Omega$,$(ii)$ $4 \, \Omega$.