True. There are forced acting on it, but as they're balanced it is unmoving
Well, the diameter of a circle is simply a length, so your measurement will have units of length. We just have to find an answer that has only units of length.
A). gram, second . . . mass and time. That can't be it.
B). kilogram, ampere . . . mass and current. That can't be it.
C). centimeter, meter . . . both lengths. This one is looking good.
D). candela, mole . . . light intensity and some chemical thing. That can't be it.
So it can't be anything else on this list but <em>C</em> .
Answer:
The coil radius of other generator is 5.15 cm
Explanation:
Consider the equation for induced emf in a generator coil:
EMF = NBAω Sin(ωt)
where,
N = No. of turns in coil
B = magnetic field
A = Cross-sectional area of coil = π r²
ω = angular velocity
t = time
It is given that for both the coils magnetic field, no. of turn and frequency is same. Since, the frequency is same, therefore, the angular velocity, will also be same. As, ω = 2πft.
Therefore, EMF for both coils or generators will be:
EMF₁ = NBπr₁²ω Sin(ωt)
EMF₂ = NBπr₂²ω Sin(ωt)
dividing both the equations:
EMF₁/EMF₂ = (r₁/r₂)²
r₂ = r₁ √(EMF₂/EMF₁)
where,
EMF₁ = 1.8 V
EMF₂ = 3.9 V
r₁ = 3.5 cm
r₂ = ?
Therefore,
r₂ = (3.5 cm)√(3.9 V/1.8 V)
<u>r₂ = 5.15 cm</u>
