Electric Circuits

How should an ammeter be connected to measure the current flowing through a resistor in a circuit?

Two resistors, $R_1 = 5 \Omega$ and $R_2 = 15 \Omega$, are connected in series. What is the equivalent resistance of this combination?

Consider a circuit with three resistors: $R_1 = 2 \Omega$, $R_2 = 4 \Omega$, and $R_3 = 6 \Omega$. $R_1$ and $R_2$ are in parallel, and this combination is in series with $R_3$. What is the total equivalent resistance of the circuit?

A battery with an internal resistance is connected to two external resistors in series. If the internal resistance of the battery is 1 \Omega, and the external resistors are $R_1 = 4 \Omega$ and $R_2 = 5 \Omega$, what is the current in the circuit if the battery's emf is 20V?

A voltmeter with a finite internal resistance is connected in parallel with a resistor in a circuit. How does this voltmeter affect the voltage reading across the resistor?

A 4 \Omega and an 8 \Omega resistor are connected in parallel. What is their equivalent resistance?

A battery has an emf of 10 V and an internal resistance of 0.5 $\Omega$. If the current flowing through the battery is 2 A, what is the terminal voltage of the battery?

A non-ideal battery with an emf $\mathcal{E}$ and internal resistance $r$ is connected to an external resistor $R$. Which expression correctly describes the power dissipated by the internal resistance?

A student connects an ammeter in series with a resistor in a simple circuit. If the ammeter has a non-negligible internal resistance, how will the measured current compare to the actual current without the ammeter?