EE055IU – Principles of EE2
Date: March 13th, 2020
Quiz #1
Time allowed: 15 mins
Circle the right answer
1. In natural response of a basis RC circuit, Vo is the initial voltage of the capacitor, and
τ is the time constant. The expression of current in resistor R is:
(15 Marks)
V
a) o e t / 
R
V
b) o e −t / 
R
V
c) o e −t / 2
R
V
d) o e − 2t / 
R
2. In a basis RC circuit, the value of time constant τ is determined by
the formula:
(15 Marks)
a)
b)
c)
d)
𝜏 = 𝑅𝐶
𝜏 = 𝐶 ⁄𝑅
𝜏 = 𝑅 ⁄𝐶
None of the above
3. A series R-C circuit consists of a resistor of 10Ω and a capacitor C. A constant
voltage source of 12V is applied to the circuit at t = 0 (as shown in the Figure). What is
the current in the circuit at t = 0? (Given that the initial voltage on the capacitor is zero).
(15 Marks)
a)
b)
c)
d)
1.2 A
1A
12 A
2A
4. In a basis RL circuit, the value of time constant τ is determined by
the formula:
a)
b)
c)
d)
𝜏 = 𝐿𝑅
𝜏 = 𝐿⁄𝑅
𝜏 = 𝑅 ⁄𝐿
None of the above
(15 Marks)
EE055IU – Principles of EE2
Date: March 13th, 2020
5. In natural response of a basis RL circuit, Io is the initial current of the inductor. The
expression of voltage on the resistor R is:
(15 Marks)
− t / LR
a) RI o e
R − Rt / L
b)
e
Io
c) RI o e − Lt / R
d) RI o e − Rt / L
6. In natural response of a basis RL circuit, when the switch is opened, the current in
the inductor:
(15 Marks)
a) does not vary with time
b) rises with time
c) first increases and then
decreases.
d) Decays with time
7. A series R-L circuit consists of resistor of 5 Ω and inductor of 1H as shown in the
Figure. A constant voltage of 20V is applied to the circuit at the moment the switch is
closed t = 0. What is the current in the circuit at t = 0.2s (given that initial current is
zero)?
(10 Marks)
a) 4(1 + e) (A)
b) 2(1- e) (A)
c) 4(1- 1/e) (A)
d) 2(1+1/e) (A)