AP EAPCET 07-Jul-2022 Shift 1 Paper

Equation of magnetic field of an electromagnetic wave is given by :
B=B0‌sin(ωt−kx)‌

∧

k

=B0‌sin(2πft−

2π

λ

.x)‌

∧

k

...[∵ω=2πf‌and‌k=

2π

λ

]
B0‌sin‌

2π

λ

[fλt−x]‌

∧

k

B=B0‌sin‌

2π

λ

[ct−x]‌

∧

k

...(i)

Also direction of B vector is perpendicular to E and also tp direction of propagation
And B0=

E0

c

Here, E0=60Vm−1
∴B0=

60

3×108

=20×10−7 Also
k=

2π

λ

Here
k=200π=

2π

λ

⇒λ=

1

100

m=

100

100

‌cm=10‌mm=10−2m
Putting the values is eq. (i), we get
B=2×10=−7‌sin[

2π

10−2

(ct−x)]‌

∧

k

=2×10−7‌sin‌200‌π(t−x)‌

∧

k