Answer:
Magnetic field, B =
(eastwards)
Explanation:
Given that,
The magnitude of electric field, E = 3.7 V/m
A plane electromagnetic wave travels northward. We need to find the magnitude and direction of the magnetic field at this instant.
The relation between the magnetic field and the electric field of the plane electromagnetic wave is given by :

c is the speed of light

So, the magnetic field is
. The direction of magnetic field is perpendicular to the electric field and the direction of wave propagation. Hence, the direction of magnetic field is eastward.
Answer:
the decay of half of the nuclei only a half-life has passed
, b) in rock time it is 1 108 years
Explanation:
The radioactive decay is given by
N = N₀
If half of the atoms have decayed
½ N₀ = N₀
½ =
₀
Ln 0.5 = - λ t
t = - ln 0.5 /λ
The definition of average life time is
= ln 2 / λ
λ = ln 2 / 
λ = 0.693 / 100 10⁶
λ = 0.693 10⁻⁸ years
We replace
t = -ln 0.5 / 0.693 10⁻⁸
t = 10⁸ years
We see that for the decay of half of the nuclei only a half-life has passed
b) in rock time it is 1 108 years
Motivation is an encouragement to do or achieve something
No because your opinion and beliefs answers many questions
Then, number of protons would be equal to number of electrons.