# Magnetic Flux and Faraday's Law

## Trending Questions

**Q.**The flux linked with a coil any instant t is given by ϕ=10t2−50t+250. instantaneous induced emF at t=35 Sec is

- 450 V
- 650 V
- 950 V
- 720 V

**Q.**

A highly conducting ring of radius R is perpendicular to and concentric with the axis of a long solenoid as shown in fig. The ring has a narrow gap of width d in its circumference. The solenoid has cross sectional area A and a uniform internal field of magnitude B0. Now beginning at t = 0, the solenoid current is steadily increased so that the field magnitude at any time t is given by B(t)=B0+αt where α>0 . Assuming that no charge can flow across the gap, the end of ring which has excess of positive charge and the magnitude of induced e.m.f. in the ring are respectively

- XπR2α

- X, Aα

- Y, πA2α

- Y, πR2α

**Q.**Shown in the figure is a circular loop of radius r and resistance R. A variable magnetic field of induction B=B0e−t is established inside the coil. If the key (K) is closed, the electrical power developed right after closing the switch is equal to

- B20π2r4R
- B20πr2R

- B010r3R

- B20π2r4R5

**Q.**Square loop ABCD of area 20cm2 and resistance 5Ω is rotated in a magnetic field B = 2T through 180∘, with field perpendicualr to the loop initially. In 0.01 seconds the magnitude of induced e.m.f is …………….

- 0.4 V
- 0.8 V
- 0.6 V
- 1.0 V

**Q.**A conducting square loop of each side `I' and resistance R moves in a plane with uniform velocity `v perpendicular to one of its sides. A magnetic induction B, constant in time and space, pointing perpendicular and into the plane of loop exists every where. The current induced in the loop is

- Zero
- BVR clock wise

- 2BVR Anti -clock wise

- BVR anti clock wise

**Q.**The north and south poles of two identical magnets approach a coil with equal speeds from opposite sides. Then

- Plate 1 will be negative and plate 2 positive
- Plate 1 will be positive and plate 2 negative
- Both the plates will be negative
- Both the plates will be positive

**Q.**In the following figure, the magnet is moved towards the coil with a speed v and induced emf is e. If magnet and coil recede away from one another each moving with speed v, the induced emf in the coil will be

- e
- 2e
- 4e
- e/2

**Q.**A uniform but time-varying magnetic field B(t) exists in a circular region of radius a and is directed into the plane of the paper, as shown. The magnitude of the induced electric field at point P at a distance r from the centre of the circular region

**Q.**A circular loop of radius R carrying current I lies in x-y plane with its centre at origin. The total magnetic flux through x-y plane is

- Zero
- Directly proportional to I
- Directly proportional to R
- Directly proportional to R2

**Q.**

A conducting square loop of side L and resistance R moves in its plane with a uniform velocity v perpendicular to one of its sides. It is sorrounded by a magnetic field B which is constant in time and space and is pointing perpendicularly into the plane of the loop. The current induced in the loop is

Zero