Answer:
Correct option is
A
450 V and 15 A
P
in
=I
p
V
p
⇒T
p
=
V
p
P
in
=
200N
3000W
=15A
Efficciencyofthetransformer
η=
P
in
P
out
=
V
p
I
p
V
s
I
s
⇒
100
90
=
3000
6V
s
V
s
=
100×6
90×5000
=450V
Hence,
option (A) is correct answer.
When the current flow ceases, the magnetic flow also decreases
The velocity of tennis racket after collision is 14.96m/s
<u>Explanation:</u>
Given-
Mass, m = 0.311kg
u1 = 30.3m/s
m2 = 0.057kg
u2 = 19.2m/s
Since m2 is moving in opposite direction, u2 = -19.2m/s
Velocity of m1 after collision = ?
Let the velocity of m1 after collision be v
After collision the momentum is conserved.
Therefore,
m1u1 - m2u2 = m1v1 + m2v2


Therefore, the velocity of tennis racket after collision is 14.96m/s
Answer: 9.9%
Explanation: efficiency = (work output /work input) × 100
Note that, 1 kilocalorie = 4184 joules, hence 22kcal = 22× 4184 = 92048 joules.
Work output = 9200 j and work input = 92048 j
Efficiency = (9200/92048) × 100 = 0.099 × 100 = 9.9%
Flow of electrons through a copper wire