In the circuit shown, $R_1$ is increased. What happens to the reading of the voltmeter (ideal)?

A voltmeter is connected in parallel with a variable resistance $R$ which is in series with an ammeter and a cell as shown in the figure. For one value of $R,$ the ammeter and voltmeter read as $0.3 \mathrm{A}$ and $0.9 \mathrm{V}$ respectively. For another value of $R$ the readings are $0.25 \mathrm{A}$ and $1.0 \mathrm{V}\text{ respectively}$ What is the internal resistance of the cell?

A combination of five resistors are connected with a cell of emf $10 V$ as shown in figure. The potential difference $V_B-V_E$ will be

In the meter bridge shown below, the resistance $X$ has a negative temperature coefficient of resistance. Neglecting the variation in other resistors, when current is passed for some time in the circuit, balance point should shift towards