This is the Doppler effect.
1. As the sound leaves the horn the sound waves are at first close to each other and as they move outwards they become further apart. The closer the sound waves are the louder the noise.
As the car gets the closer the sound waves get closer, so the horn becomes louder.
2. As the horn moves away, the sound waves become less frequent, causing the pitch to get lower.
Answer:
L= 2 mH
Explanation:
Given that
Frequency , f= 10 kHz
Maximum current ,I = 0.1 A
Maximum energy stored ,E= 1 x 10⁻⁵ J
The maximum energy stored in the inductor is given as follows

Where ,L= Inductance
I=Current
E=Energy
Now by putting the values in the above equation


L=0.002 H
L= 2 mH
We know that frequency f is given as

C=Capacitance , f=frequency ,L=Inductance
Now by putting the values






Therefore the inductance and capacitance will be 2 mH and 1.26 x 10⁻⁷ F respectively.
Momentum before the hit:
p = mv = 0.01 * 300 + 1 * 0
Momentum after the hit:
p = 0.01 * 150 + 1 * v
Momentum is conserved:
0.01 * 300 = 0.01 * 150 + v
3 = 1.5 + v
v = 1.5
The velocity of the block after the collision is 1.5 m/s.
Answer:
B.The charge on A is -q; there is no charge on B.
Explanation:
We are given that
Charge=+q
We have to find the correct statement.
When positive charge is placed at center of uncharged metal sphere
insulated from the ground then negative charge(-q) induced on inner
surface A of sphere and the outer surface B is grounded then the surface is neutral .
It means there is no charge on surface B.
Hence, option B is true .
B.The charge on A is -q; there is no charge on B.
I’m sorry if i took up a lot of space, hope this is a valid approximate answer