Advertisements
Advertisements
प्रश्न
A long straight current carrying wire passes normally through the centre of circular loop. If the current through the wire increases, will there be an induced emf in the loop? Justify.
Advertisements
उत्तर
No, there will be no induced emf in the loop as there is no change in the magnetic flux linked with the circular loop because magnetic field lines are parallel to the plane of the loop.
ϕ=B.A
As the angle between the field line and the area vector is 90 degrees, we have zero flux linked with the loop.
ϕ=BAcosθ
ϕ=BAcos90°ϕ=0
APPEARS IN
संबंधित प्रश्न
A cell of emf 'E' and internal resistance 'r' is connected across a variable load resistor R. Draw the plots of the terminal voltage V versus (i) R and (ii) the current I.
It is found that when R = 4 Ω, the current is 1 A and when R is increased to 9 Ω, the current reduces to 0.5 A. Find the values of the emf E and internal resistance r.
The earth’s surface has a negative surface charge density of 10−9 C m−2. The potential difference of 400 kV between the top of the atmosphere and the surface results (due to the low conductivity of the lower atmosphere) in a current of only 1800 A over the entire globe. If there were no mechanism of sustaining atmospheric electric field, how much time (roughly) would be required to neutralise the earth’s surface? (This never happens in practice because there is a mechanism to replenish electric charges, namely the continual thunderstorms and lightning in different parts of the globe). (Radius of earth = 6.37 × 106 m.)
A 10 V cell of negligible internal resistance is connected in parallel across a battery of emf 200 V and internal resistance 38 Ω as shown in the figure. Find the value of current in the circuit.
Two identical cells, each of emf E, having negligible internal resistance, are connected in parallel with each other across an external resistance R. What is the current through this resistance?
Can the potential difference across a battery be greater than its emf?
Five cells each of emf E and internal resistance r send the same amount of current through an external resistance R whether the cells are connected in parallel or in series. Then the ratio `("R"/"r")` is:
A cell of emf E and internal resistance r is connected across an external resistance R. Plot a graph showing the variation of P.D. across R, versus R.
Internal resistance of a cell is the resistance offered by which component?
The relationship between terminal potential difference (V), EMF (ε), current (I), and internal resistance (r) is given by:
Internal resistance of a cell is affected by the surface area of electrodes. As surface area increases, internal resistance:
