Answer:
B=μ₀I/2r
Explanation:
Produced magnetic field due to an existing electric field through a coil or conductor can be explained by Biot-Savart Law. Formula for this law is:
dB=(μ₀I/4π.r²)dL
Here,
r=Radius of the loop
I and r are constants with respect to length L.
To convert linear displacement L into angular displacement Ф:
dL=r.dФ
So,
dB=(μ₀I/4π.r²)r.dФ
dB=(μ₀I/4π.r)dФ
Integrating both sides over the circle i.e. from 0 radians to 2π radians (360⁰), while the integration will apply only on dФ as all others are constants.
B=(μ₀I/4πr)(2π-0)
<u>B=(μ₀I/2r)</u>
I think it's D cuz D is the heliocentric theory
Answer:
Resistance in the flash tube, 
Explanation:
It is given that,
Speed of the bullet, v = 500 m/s
Distance between one RC constant, d = 1 mm = 0.001 m
Capacitance, 
The time constant of RC circuit is given by :

R is the resistance in the flash tube
..........(1)
Speed of the bullet is given by total distance divided by total time taken as :




Equation (1) becomes :


So, the resistance in the flash tube is
. Hence, this is the required solution.