0

Guest

Courses New

A sensitive electronic device of resistance 175 is to be connected to a source of emf by a switch. The device is designed to operate with a current of 36 mA , but to avoid damage to the device, the current can rise to no more than 4.9 mA in the first 58 sec. after the switch is closed. To protect the device it is connected in series with an inductor What is the time constant ?


A sensitive electronic device of resistance 175 is to be connected to a source of emf by a switch. The device is designed to operate with a current of 36 mA , but to avoid damage to the device, the current can rise to no more than 4.9 mA in the first 58 sec. after the switch is closed. To protect the device it is connected in series with an inductor

 What is the time constant ?


Grade:11

1 Answers

ROSHAN MUJEEB
askIITians Faculty 833 Points
3 years ago
he emf of the source is 0.864, inductance L = 7 x 10^-2 H and time constant is t = 4 x 10^-4 s
Explanation:

P = 175 Ω
io = 36 x 10^-3 A
V = io R = 6.3 V
i = io ( 1 - e^-t/z)
4.9 = 36 ( 1 - e^-t/z)

e^-t/z = 1 - 4.9 / 36 = 0.864

t / tL = 0.146 => t / L/R = 0.146

L = Rt / 0.146

L = 175 x 5.8 x 10^-6 / 0.146

L = 7 x 10^-2 H

tL = 7 x 10^-2 H / 175 = 4 x 10^-4 s

Hence the emf of the source is 0.864, inductance L = 7 x 10^-2 H and time constant is t = 4 x 10^-4 s


Think You Can Provide A Better Answer ?

Other Related Questions on Magnetism

View all Questions »

ASK QUESTION

Get your questions answered by the expert for free

Answer and earn gift vouchers

Win Gift vouchers upto Rs 500/-

View courses by askIITians

Design classes One-on-One in your own way with Top IITians/Medical Professionals

Click Here Know More

Complete Self Study Package designed by Industry Leading Experts

Click Here Know More

Live 1-1 coding classes to unleash the Creator in your Child

Click Here Know More

a Complete All-in-One Study package Fully Loaded inside a Tablet!

Click Here Know More