Answer:Thus, The magnetic field around a current-carrying wire is <u><em>directly</em></u> proportional to the current and <u><em>inversely</em></u> proportional to the distance from the wire. If the current triples while the distance doubles, the strength of the magnetic field increases by <u><em>one and half (1.5)</em></u> times.
Explanation:
Magnetic field around a long current carrying wire is given by

where B= magnetic field
permeability of free space
I= current in the long wire and
r= distance from the current carrying wire
Thus, The magnetic field around a current-carrying wire is <u><em>directly</em></u> proportional to the current and <u><em>inversely</em></u> proportional to the distance from the wire.
Now if I'=3I and r'=2r then magnetic field B' is given by

Thus If the current triples while the distance doubles, the strength of the magnetic field increases by <u><em>one and half (1.5)</em></u> times.
Answer:
The skater's speed after she stops pushing on the wall is 1.745 m/s.
Explanation:
Given that,
The average force exerted on the wall by an ice skater, F = 120 N
Time, t = 0.8 seconds
Mass of the skater, m = 55 kg
It is mentioned that the initial sped of the skater is 0 as it was at rest. The change in momentum of skater is :

The change in momentum is equal to the impulse delivered. So,

So, the skater's speed after she stops pushing on the wall is 1.745 m/s.
Answer: 0.016 h
Explanation:

It is given that, biker has an average speed = 18 km/h
Total distance traveled = 0.30 km
Therefore, time taken by biker to travel this distance:

Thus, the biker takes 0.016 hours to travel the segment of 0.30 km at an average speed of 18 km/h.
Answer:
Maximum emf = 5.32 V
Explanation:
Given that,
Number of turns, N = 10
Radius of loop, r = 3 cm = 0.03 m
It made 60 revolutions per second
Magnetic field, B = 0.5 T
We need to find maximum emf generated in the loop. It is based on the concept of Faraday's law. The induced emf is given by :

For maximum emf, 
So,

So, the maximum emf generated in the loop is 5.32 V.
Answer:
The friend on moon will be richer.
Explanation:
We must calculate the mass of gold won by each person, to tell who is richer. For that purpose we will use the following formula:
W = mg
m = W/g
where,
m = mass of gold
W = weight of gold
g = acceleration due to gravity on that planet
<u>FOR FRIEND ON MOON</u>:
W = 1 N
g = 1.625 m/s²
Therefore,
m = (1 N)/(1.625 m/s²)
m(moon) = 0.6 kg
<u>FOR ME ON EARTH</u>:
W = 1 N
g = 9.8 m/s²
Therefore,
m = (1 N)/(9.8 m/s²)
m(earth) = 0.1 kg
Since, the mass of gold on moon is greater than the mass of moon on earth.
<u>Therefore, the friend on moon will be richer.</u>