Home
Class 12
PHYSICS
Following figure shows a metal rod PQ re...

Following figure shows a metal rod PQ resting on the smooth ralls AH and positioned between the poles of a permanent magnet. The rails, the rod and the magnetic field are in three mutual perpendicular directions. A galvanometer G connects the rails through a switch K. Length of the rod 15 cm, B 0.50 T, resistance of the closed loop containing the rod `9.0 mOmega`. Assume the field to be uniform.
Suppose K is open and the rod is moved with a speed of `12"cm s"^(-1)` in the direction shown. Give the polarity and magnitude of the induced emf.

Text Solution

Verified by Experts

Given, length of the rod `l=15cm=15xx10^(-2)m` Magnetic field `B=0.50T`
Resistance of the closed - loop containing the rod, `R=9mOmega=9xx10^(-3)Omega`
Velocity of rod `V=12" cm/s "12 xx 106(-2) m//s.`
The magnitude of the motional emf `e=BVl=0.50xx12xx10^(-2)xx15xx10^(-2),e=9xx10^(-3)V`
According to the Fleming's left hand rule, the direction of Lorentz force `(f =-e(V xx B))` on electrons in PQ is from P to Q. So, p would acquire positive charge and Q would acquire negative charge.
Promotional Banner

Topper's Solved these Questions

  • ELECTROMAGNETIC INDUCTION

    VIKRAM PUBLICATION ( ANDHRA PUBLICATION)|Exercise Textual Exercise|18 Videos

  • ELECTRIC CHARGES AND FIELDS

    VIKRAM PUBLICATION ( ANDHRA PUBLICATION)|Exercise DAM SURE LAQ|1 Videos

  • ELECTROMAGNETIC WAVE

    VIKRAM PUBLICATION ( ANDHRA PUBLICATION)|Exercise ADDITIONAL EXERCISES|19 Videos

Similar Questions

Explore conceptually related problems

Figure 6.20 shows a metal rod PQ resting on the smooth rails AB and positioned between the poles of a permanent magnet. The rails, the rod, and the magnetic field are in three mutual perpendicular directions. A galvanometer G connects the rails through a switch K. Length of the rod = 15 cm, B = 0.50 T, resistance of the closed loop containing the rod = 9.0 m Omega . Assume the field to be uniform. (a) Suppose K is open and the rod is moved with a speed of 12 cm s^(-1) in the direction shown. Give the polarity and magnitude of the induced emf. (b) Is there an excess charge built up at the ends of the rods when K is open? What if K is closed? (c) With K open and the rod moving uniformly, there is no net force on the electrons in the rod PQ even though they do experience magnetic force due to the motion of the rod. Explain. (d) What is the retarding force on the rod when K is closed? (e) How much power is required (by an external agent) to keep the rod moving at the same speed (=12 cm s^(-1) ) when K is closed? How much power is required when K is open? (f ) How much power is dissipated as heat in the closed circuit? What is the source of this power? (g) What is the induced emf in the moving rod if the magnetic field is parallel to the rails instead of being perpendicular?

Following figure shows a metal rod PQ resting on the smooth ralls AH and positioned between the poles of a permanent magnet. The rails, the rod and the magnetic field are in three mutual perpendicular directions. A galvanometer G connects the rails through a switch K. Length of the rod 15 cm, B 0.50 T, resistance of the closed loop containing the rod 9.0 mOmega . Assume the field to be uniform. What is the retarding force on the rod when K is closed?

Following figure shows a metal rod PQ resting on the smooth ralls AH and positioned between the poles of a permanent magnet. The rails, the rod and the magnetic field are in three mutual perpendicular directions. A galvanometer G connects the rails through a switch K. Length of the rod 15 cm, B 0.50 T, resistance of the closed loop containing the rod 9.0 mOmega . Assume the field to be uniform. How much power is dissipated as heat in the closed circuit ? What is source of this power?

Following figure shows a metal rod PQ resting on the smooth ralls AH and positioned between the poles of a permanent magnet. The rails, the rod and the magnetic field are in three mutual perpendicular directions. A galvanometer G connects the rails through a switch K. Length of the rod 15 cm, B 0.50 T, resistance of the closed loop containing the rod 9.0 mOmega . Assume the field to be uniform. What is the induced emf in the moving rod if the magnetic field is parallel to the rails instead of being perpendicular?

IF a copper rod carries a direct current,then where will the magnetic field in the conductor?

An iron rod of length 2l is sliding on two mutually perpendicular lines . Find the locus of the midpoint of the rod.