Answer:

Explanation:
Given that
For straight wire
Charge density= λ
For hollow metal cylinder
Charge density=2 λ
We know that electric filed for wire given as


Now the electric filed due to hollow metal cylinder


Now by considering the Gaussian surface r<R then only electric fild due to wire will present.So
At r<R

Answer:
The number of bright fringes per unit width on the screen is,
Explanation:
If d is the separation between slits, D is the distance between the slit and the screen and
is the wavelength of the light. Let x is the number of bright fringes per unit width on the screen is given by :

is the wavelength
n is the order
If n = 1,

So, the the number of bright fringes per unit width on the screen is
. Hence, the correct option is (B).
Answer:
Ratio = 1:1
Explanation:
= initial momentum of the system
= final momentum of the system
For the momentum to be conserved , final total momentum must be equal to initial total momentum, so we have

Dividing both side by
, we get

hence
Ratio = 1
Answer:
The intensity of sound at a rock concert is louder than that of a whisper by a factor of 1 x 10¹⁰
Explanation:
Given;
rock concert sound intensity level, β₁ = 120 dB
whisper sound intensity level, β₂ = 20 dB
The sound intensity level is given as;

where;
I₀ is the threshold sound intensity of hearing = 10⁻¹² W/m²
I is the sound intensity
Intensity of sound at rock concert ;

The intensity of sound of a whisper;

Determine the factor by which the intensity of sound at a rock concert louder than that of a whisper

Therefore, the intensity of sound at a rock concert is louder than that of a whisper by a factor of 1 x 10¹⁰
Answer:
In a standing sound wave in a pipe, nodes are regions of mean atmosphere pressure and low displacement.