How many $176 \,\Omega$ resistors (in parallel) are required to carry $5 \,A$ on a $220 \,V$ line?

When a $12\, V$ battery is connected across an unknown resistor,there is a current of $2.5\, mA$ in the circuit. Find the value of the resistance of the resistor.

An electric lamp of $100 \,\Omega$,a toaster of resistance $50 \,\Omega$,and a water filter of resistance $500 \,\Omega$ are connected in parallel to a $220 \,V$ source. What is the resistance of an electric iron connected to the same source that takes as much current as all three appliances,and what is the current through it?

How is a voltmeter connected in the circuit to measure the potential difference between two points?

An electric motor takes $5\, A$ from a $220\, V$ line. Determine the power of the motor and the energy consumed in $2\, h$.

Draw a schematic diagram of a circuit consisting of a battery of three cells of $2\, V$ each,a $5 \,\Omega $ resistor,an $8\,\Omega $ resistor,and a $12\,\Omega $ resistor,and a plug key,all connected in series.