Basic Electrical Circuits - Week 9 Solutions

 Carefully read the questions and try to solve them intuitively.

Multiple questions can have the same circuit figure.

1 point

Find the time constant of the following circuit shown in figure 1.

1μs$1��$

0.33μs$0.33��$

0.5μs$0.5��$

0.66μs$0.66��$

For the circuit shown in figure 2, the switch is opened at t = 0. Determine the time necessary for the capacitor voltage to decay to one-third of its value at t = 0. (Answer should be in milliseconds)

1 point

Find the time constant in the following circuit(Answer should be in seconds)

1 point

1 point

Find the time constant of the circuit shown in figure 4. (NOTE: The switch S closes at t = 0 sec)

710$\frac{7}{10}$ sec

310$\frac{3}{10}$ sec

 1 sec

43$\frac{4}{3}$ sec

1 point

Consider the circuit given in figure 5 and find the following. 

(NOTE: The switch S is closed at time t = 0 sec and the cap is initially uncharged)

i) Vc(0+)${�}_{�}(0^{+})$           ii) Ic(0+)${�}_{�}(0^{+})$ 

0 V and IC$\frac{�}{�}$ A

 0 V and 0 A

 I V and I A

 0 V and I A

1 point

Refer to figure 5 and find the following                          

(NOTE: The switch S is closed at time t = 0 sec and the cap is initially uncharged)

i) dVc(0+)dt$\frac{�{�}_{�}(0^{+})}{��}$         ii) dIc(0+)dt$\frac{�{�}_{�}(0^{+})}{��}$        iii) d2Vc(0+)dt2$\frac{{�}^2{�}_{�}(0^{+})}{�{�}^2}$

IC$\frac{�}{�}$ , −IRC$-\frac{�}{��}$, −IRC2$-\frac{�}{�{�}^2}$

IRC$\frac{�}{��}$ , −IC$-\frac{�}{�}$, −IRC2$-\frac{�}{�{�}^2}$

IC$\frac{�}{�}$ , −IRC$-\frac{�}{��}$, −IR2C$-\frac{�}{{�}^2�}$

IRC$\frac{�}{��}$, −IC$-\frac{�}{�}$, −IR2C$-\frac{�}{{�}^2�}$

1 point

Find the time ‘t’ at which the voltage across both inductor and resistor is the same. Initially the inductor is relaxed. (T = Time constant)

 T sec

 T ln 2 sec

 ln 2 sec

Tln2$\frac{�}{��2}$ sec

Find the current i(t) after t = 0.5 sec in figure 7. The current should be in Amps. (NOTE: The switch is closed at t = 0 sec. Initially the inductor is relaxed. The answer should be correct up-to 2 decimal places.)

1 point

The value of i(t) at t = 2 sec in the circuit shown in figure 8 is _______ Amps in figure 8. (correct up-to two places of decimal)

1 point

1 point

The steady state value of i(t) is

 3 A

 2 A

 1 A

 0 A

1 point

The time constant of the circuit given in figure 10 is

19$\frac{1}{9}$ sec

14$\frac{1}{4}$ sec

 4 sec

 9 sec

1 point

In the above circuit (Figure 11), the peak value of capacitor voltage is

 11 V

 5.5 V

 6.32 V

 0.96 V