wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

The electric field ( in NC-1) in an electromagnetic wave is given by E=50sinω(t-xc).The energy stored in a cylinder of cross-section 10cm2 and length 100cmalong the x-axis will be


A

5.5×10-12J

No worries! We‘ve got your back. Try BYJU‘S free classes today!
B

1·1×10-11J

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
C

2·2×10-11J

No worries! We‘ve got your back. Try BYJU‘S free classes today!
D

1·65×10-11J

No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is B

1·1×10-11J


Step 1: Given data

Electric field E=50sinω(t-xc)

Area of the cylinder A=10cm2=10×10-4m2

Length l=100cm=100×10-2m=1m

Step 2: Formula used

The energy density can be computed using the following formula:

U=12εE21

Where U=energy density, ε=permittivity and E=electric field

Energy=Energydensity×volume2

VolumeV=AreaA×Lengthl3

Step 3: Compute the Volume:

Substitute known values in the equation 3 to obtain the volume.

V=10×10-4×1V=10-3m3

Step 3: Compute energy density

From the equation E=50sinω(t-xc), it is clear that Eo=50

Substitute the known values in the equation 1.

U=12×8.85×1012×502U=1.1×108Jm3

Step 4: Compute stored energy

Substitute the value of energy density and volume in equation 2.

=1.1×10-8×10-3=1.1×10-11J

Thus, the energy stored in a cylinder is 1.1×10-11J.

Hence, option B is the correct answer.


flag
Suggest Corrections
thumbs-up
3
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Electromagnetic Spectrum
PHYSICS
Watch in App
Join BYJU'S Learning Program
CrossIcon