Download App

Electromagnetic Induction — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsElectromagnetic Induction3 Marks
Question
The current generator Ig shown in figure, sends a constant current i through the circuit. The wire cd is fixed and ab is made to slide on the smooth, thick rails with a constant velocity v towards right. Each of these wires has resistance r. Find the current through the wire cd.

✓

Answer


Initial current passing = i

Hence initial emf = ir

Emf due to motion of ab = Blv

Net emf = ir - Blv

Net resistance = 2r

Hence current passing $=\frac{\text{ir}-\text{Blv}}{2\text{r}}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "3 Marks Question" from Electromagnetic Induction→Electromagnetic Induction — all question types→Physics STD 12 Science question papers→Gujarat Board STD 12 Science question papers→Gujarat Board question paper generator→

Similar questions

State the underlying principle of a cyclotron. Explain its working with the help of a schematic diagram. Obtain the expression for cyclotron frequency.
→
A monochromatic light source of intensity 6mW emits 8 × 1016 photons per second. This light ejects photoelectrons from a metal surface. The stopping potential for this setup is 2.0V. Calculate the work function of the metal.
→
A metallic rod of length ‘l’ is rotated with a frequency v with one end hinged at the centre and the other end at the circumference of a circular metallic ring of radius r, about an axis passing through the centre and perpendicular to the plane of the rinig. A constant uniform magnetic field B parallel to the axis is present every where. Using Lorentz force, explain how emf is induced between the centre and the metallic ring and hence obtain the expression for it.
→
A long, straight wire carries a current. Is Ampere's law valid for a loop that does not enclose the wire? That encloses the wire but is not circular?
→
A river 400m wide is flowing at a rate of 2.0m/s. A boat is sailing at a velocity of 10m/s with respect to the water, in a direction perpendicular to the river.
  1. Find the time taken by the boat to reach the opposite bank.
  2. How far from the point directly opposite to the starting point does the boat reach the opposite bank?
→
Draw V – I characteristics of a p–n junction diode. Answer the following questions, giving reasons:
  1. Why is the current under reverse bias almost independent of the applied potential up to a critical voltage?
  2. Why does the reverse current show a sudden increase at the critical voltage?
Name any semiconductor device which operates under the reverse bias in the breakdown region.
→
When a compass needle be placed at magnetic north pole, how would it behave? If a dip needle be placed at the place, how would it behave?
→
A metre stick is held vertically with one end on a rough horizontal floor. It is gently allowed to fall on the floor. Assuming that the end at the floor does not slip, find the angular speed of the rod when it hits the floor.
→
The work function for the following metals is given:
Na: 2.75 eV; K: 2.30 eV; Mo: 4.17 eV; Ni: 5.15 eV. Which of these metals will not give photoelectric emission for a radiation of wavelength 3300 Å from a He-Cd laser placed 1 m away from the photocell? What happens if the laser is brought nearer and placed 50 cm away?
→
A string of length 20cm and linear mass density 0.40g/cm is fixed at both ends and is kept under a tension of 16N. A wave pulse is produced at t = 0 near an end as shown in figure, which travels towards the other end.
  1. When will the string have the shape shown in the figureagain
  2. Sketch the shape of the string at a time half of that found in part (a).
→