The magnetic field strength of a very long current-carrying wire is proportional to the inverse of the distance from the wire. The farther you go from the wire, the weaker the magnetic field becomes.
B ∝ 1/d
B = magnetic field strength, d = distance from wire
Calculate the scaling factor for d required to change B from 25μT to 2.8μT:
2.8μT/25μT = 1/k
k = 8.9
You must go to a distance of 8.9d to observe a magnetic field strength of 2.8μT
The answer is D. Electric resistance increases with an increase in the length of a wire and as a result current flow decreases. There is a direct relationship between the length of the wire and the resistance. The longer the wire, the more resistance there will be. Additionally, from Ohm's Law, current is inversely proportional to resistance. This means as the current increases, resistance decreases or vice versa.
Answer:
Option B
Explanation:
Looking at the 3 galvanometer readings given above, for galvanometer A, the reading is -2 mA.
For galvanometer B, the reading is 4 mA.
While for galvanometer C, the reading is -5 MA
Thus, option B is correct.
15.49 should be the answer if that is 12 watt battery.
Answer:
=20 turns
Explanation:
The given case is a step down transformer as we need to reduce 120 V to 6 V.
number of turns on primary coil N_{P}= 400
current delivered by secondary coil I_{S}= 500 mA
output voltage = 6 V (rms)
we know that
putting values we get
to calculate number of turns in secondary
therefore, =20 turns
