An ac voltmeter with a large impedance is connected in turn across the inductor, the capacitor, and the resistor in a series circuit having an alternating emf of $\mathbf{100}\mathbf{}\mathbf{\text{V}}$ (RMS); the meter gives the same reading in volts in each case. What is this reading?

Alternating emf $=100\text{V}$

Whenever we connect an electronic device (with high impedance) to another circuit with finite impedance in parallel, there is no effect on the impedance of the circuit. In this case, we are connecting the voltmeter with different components.

Whenever there isa connection between an electronicdevice (with high impedance) with another device with finite impedance in parallel, there is no effect on the impedance of the circuit.

Therefore, since the ac voltmeter is connected in parallel with the inductor, in this case, the voltmeter reading will be$100\text{V}$.

Since the ac voltmeter is connected in parallel with the resistor, in this case, the voltmeter reading will be$100\text{V}$.

Since the ac voltmeter is connected in parallel with the capacitor, in this case, the voltmeter reading will be $100\text{V}$.