Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

the component in the upper branch is an ideal 2.9 A fuse. It has zero resistance

ID: 2258907 • Letter: T

Question


the component in the upper branch is an ideal 2.9 A fuse. It has zero resistance as long as the current through it remains less than 2.9 A. If the current reaches 2.9 A it 'blows' and thereafter has infinite resistance. Switch S is closed at time t = 0 . Use the numerical values : E=12 V, L=5.7 H.


When does the fuse blow ?

s

the component in the upper branch is an ideal 2.9 A fuse. It has zero resistance as long as the current through it remains less than 2.9 A. If the current reaches 2.9 A it 'blows' and thereafter has infinite resistance. Switch S is closed at time t = 0 . Use the numerical values : E=12 V, L=5.7 H. When does the fuse blow ?

Explanation / Answer

Since the resistor is in parallel with the fuse which is 0 ohms, we can ignore the resistor.

V= L*di/dt in a purely inductive circuit.

Rearrange to Time = Current*Inductance/Voltage

t = IL/V =2.9*5.7/12 =1.3775 seconds or approx 1.38 seconds