When do we say that the resistors are connected in series?

Who discovered the electron?

The potential difference across a conductor is doubled,the rate of generation of heat will

When a high resistance voltmeter is connected directly across an electric bulb,its reading is $2 \ V$. An electric cell is sending a current of $0.4 \ A$ (measured by an ammeter) in the electric circuit.
$(a)$ Draw the circuit.
$(b)$ Find the resistance of the electric bulb.
$(c)$ State the law that is applied for making these calculations. If a graph is plotted between $V$ and $I$,show the nature of the graph obtained.

$(a)$ Give reasons why tungsten is used for making the filament of electric lamps.
$(b)$ Why are the heating elements of electrical appliances made up of an alloy rather than a pure metal?

Find out the following in the electric circuit given in the figure:
$(a)$ Effective resistance of two $8\,\Omega$ resistors in the combination.
$(b)$ Current flowing through the $4\,\Omega$ resistor.
$(c)$ Potential difference across the $4\,\Omega$ resistor.
$(d)$ Power dissipated in the $4\,\Omega$ resistor.
$(e)$ Difference in ammeter readings,if any.