Answer: B
Explanation:
Magnetic fields are created due to charges in motion. Current by definition is the amount of charge flowing over time. Therefore, the answer is B, when an electric current flows through a wire.
Answer:
E = 307667 N/C
Explanation:
Since the object's mass is 1 g, then its weight in newtons is 0.001 * 9.8 = 0.0098 N.
This weight should have the same magnitude of the vertical component of the tension T of the string (T * cos(37)) so we can find the magnitude of the tension T via:
0.0098 N = T * cos(37)
then T = 0.0098/cos(37) N = 0.01227 N
Knowing the tension's magnitude, we can find its horizontal component:
T * sin(37) = 0.007384 N
and now we can obtain the value of the electric field since we know the charge of the ball to be: -2.4 * 10^(-8) C:
0.007384 N = E * 2.4 * 10^(-8) C
Then E = 0.007384/2.4 * 10^(-8) N/C
E = 307667 N/C
The energy of a single photon is given by
where
is the Planck constant
f is the frequency of the wave (of the photon)
In our problem, the radio wave has a frequency of
, so if we put this value into the previous formula, we can find the energy of a single photon of this electromagnetic wave:
Answer:
Explanation:
Let say the ball is projected at an angle with horizontal
So here two components of the velocity of the ball is given as
now the displacement in x direction is given as
in y direction it is given as
now from above two equations