A. Light CAN travel through a vacuum. It is an electromagnetic transverse wave, and thus needs no medium.
Answer:
The wave is traveling in the +x direction.
Explanation:
The equation of a wave is given by the formula as :
Here,
A is the amplitude of wave
is the phase of wave
is the angular frequency of the wave
We need to find the correct statement out of given options. The given equation can be rewritten as :
Here, the propagation constant is negative. So, the wave is moving in +x direction. Hence, the correct option is (a).
Physical forces because physical force can only move the box
Answer:
Explanation:
We shall apply Gauss's theorem for electric flux to solve the problem . According to this theorem , total electric flux coming out of a charge q can be given by the following relation .
∫ E ds = q / ε
Here q is assumed to be enclosed in a closed surface , E is electric intensity on the surface so
∫ E ds represents total electric flux passing through the closed surface due to charge q enclosed in the surface .
This also represents total flux coming out of the charge q on all sides .
This is equal to q / ε where ε is a constant called permittivity which depends upon the medium enclosing the charge . For air , its value is 8.85 x 10⁻¹² .
If charge remains the same but radius of the sphere enclosing the charge is doubled , the flux coming out of charge will remain the same .
It is so because flux coming out of charge q is q / ε . It does not depend upon surface area enclosing the charge . It depends upon two factors
1 ) charge q and
2 ) the permittivity of medium ε around .
