In an alternating current circuit consisting of elements in series, the current increases on increasing the frequency of the supply. Which of the following elements are likely to constitute the circuit?
(a) Only resistor
(b) Resistor and an inductor
(c) Resistor and a capacitor
(d) Only a capacitor

Choose the correct options:

1. (b), (c) 2. (a), (d)
3. (b), (d) 4. (c), (d)
(4) 
Hint: The current in the circuit depends on the impedance.
Step 1: According to the question, the current increases on increasing the frequency of the supply. Hence, the reactance of the circuit must be decreasing as increasing frequency.
Step 2: For a capacitive circuit,
                                         XC=1ωC=12πνC
Clearly when frequency increases, XC decreases,
For R-C circuit,           X=R2+1ωC2
when frequency increases X decreases.