Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • NCERT
  • A telephone cable at a place has four long straight horizontal wires carrying a current of 1.0 A in the same direction east to west. The

5.19 A telephone cable at a place has four long straight horizontal wires carrying a current of 1.0 A in the same direction from east to west. The earth’s magnetic field at the place is 0.39 G, and the angle of dip is 35 \degree. The magnetic declination is nearly zero. What are the resultant magnetic fields at points 4.0 cm below the cable?

Answers (1)

Number of long straight horizontal wires = 4

The current carried by each wire = 1A

 earth’s magnetic field at the place = 0.39 G

the angle of dip = 350

magnetic field due to infinite current-carrying straight wire

B'=\frac{\mu_0I}{2\pi r}

r=4cm =0.04 m

B'=\frac{4\pi\times10^{-7}\times1}{2\pi \times4\times10^{-2}}

magnetic field due to such 4 wires

B=4\times \frac{4\pi\times10^{-7}\times1}{2\pi \times4\times10^{-2}}=2\times10^{-5}T

The horizontal component of the Earth's magnetic field

H=0.39\times10^{-4}cos35=0.319\times10^{-4}T=3.19\times10^{-5}T

the horizontal component of the Earth's magnetic field

V=0.39\times10^{-4}sin35=0.22\times10^{-4}T=2.2\times10^{-5}T

At the point below the cable

H'=H-B=3.19\times10^{-5}-2\times10^{-5}=1.19\times10^{-5}T

The resulting field is

\sqrt{H'^2+V^2}=\sqrt{(1.19\times10^{-5})^2+(2.2\times10^{-5})^2}=2.5\times10^{-5}T=0.25G

 

Posted by

Safeer PP

View full answer

Crack CUET with india's "Best Teachers"

  • HD Video Lectures
  • Unlimited Mock Tests
  • Faculty Support
cuet_ads

Similar Questions

Trending Articles/News

anam-khan

CBSE Board Exams 2025: Counselling for students, parents from February 1
anam-khan

CBSE asks schools to include APAAR IDs in school ID after NTA says ‘not mandatory’ for NEET
anam-khan

CBSE Board Exams 2025: What the ethics code bans from exam centres

Latest Question