A square of side L meters lies in the x-y plane in a region where the magnetic field is given by B = B₀ (2ˆi + 3ˆj + 4kˆ) Tesla, where B₀ is constant. The magnitude of flux passing through the square Is
(A) 2B₀L² Wb
(B) 3B₀L² Wb
(C) 4B₀L² Wb
(D) √(29) B₀L² Wb
(A) 2B₀L² Wb
(B) 3B₀L² Wb
(C) 4B₀L² Wb
(D) √(29) B₀L² Wb
(C) 4B₀L² Wb
The magnetic flux linked with a coil is given by the equation Ø = 2t² + 2t + 4 weber. The magnitude of induced emf at time t=2s will be
(a) 16 V
(b) 10V
(c) 12V
(d) 8V
A square loop of side l , resistance R is placed in a uniform magnetic field B acting normally to the plane of the loop. If we attempt to pull it out of the field with a constant velocity v , then the power needed is
(a) BRlv
(b) B²l²v²/R
(c) B l²v²/ R
(d) Blv/R
In a circuit with a coil of resistance 3Ω, the magnetic flux changes from 1.0 Wb to 10.0 Wb in 0.3 s. The charge that flows in the coil during this time is
(a) 2.0 C
(b) 3.0 C
(c) 4.0 C
(d) 1.0 C
The magnetic flux linked with a coil is given by an equation Φ = 5t² + 2t + 3. The induced e.m.f. in the coil at the third second will be
(A) 32 units
(B) 54 units
(C) 40 units
(D) 65 units
A long solenoid has 2000 turns. When a current of 2 A flows through it, then the magnetic flux linked with each turn of the solenoid is 2 × 10⁻³ Wb. The self inductance of the solenoid is
(a) 1 H
(b) 2 H
(c) 3 H
(d) 4 H
A coil of wire of certain radius has 500 turns and self inductance of 75 mH. The self inductance of a second similar coil of 600 turns will be
(a) 100 mH
(b) 150mH
(c) 108 mH
(d) 105mH
Two currents loops are concentric and lie in the same plane. The current in the outer loop is anti clockwise and increasing with time. The induced current in the inner loop ,is
(a) Clockwise
(b) Zero
(c) Counter-clockwise
(d) None of these
A dip circle is so set that it moves freely in the magnetic meridian. The angle of dip is 40°. Now the dip circle is rotated so that the plane in which the needle moves makes an angle of 30° with the magnetic meridian. In this position, the needle will dip by the angle
The electric potential of earth is taken to be zero, because earth is a good
(a) insulator
(b) conductor
(c) semiconductor
(d) dielectric
A parrot comes and sits on a bare high-power line. It will
A. experience a mild shock
B. experiences a strong shock
C. get killed instantaneously
D. not be affected at all
The speed of light in air is 3 × \(10^8\) m/s. If the refractive index of glass is 1.5, find the time taken by light to travel a distance 50 cm in glass.
(a) 2.5 × \(10^{-9}\) sec.
(b) 0.5 × \(10^{-9}\) sec.
(c) 0.16 × \(10^{-9}\) sec.
(d) 3 × \(10^{-9}\) sec.
The figure below shows a potentiometer with a cell of 2.0 V and internal resistance 0.40 Ω maintaining a potential drop across the resistor wire AB. A standard cell which maintains a constant emf of 1.04 V (for very moderate currents up to a few mA) gives a balance point at 67.3 cm length of the wire. To ensure very low currents drawn from the standard cell, a very high resistance of 600 KΩ is put in series with it, which is shorted close to the balance point. The standard cell is then replaced by a cell of unknown emf Ꜫ and the balance point, found similarly, turns out to be at 82.3 cm length of the wire. What is the value Ꜫ?
(a) 0.25 V
(b) 2.25 V
(c) 3.25 V
(d) 1.25 V
An optically active compound
(a) rotates the plane of polarised light.
(b) changes the direction of polarised light.
(c) does not allow plane polarised light to pass through.
(d) none of these.
In a meter bridge as shown, the balance point is found to be at 39.5 cam from the end A, when the resistor Y is of 12.5 Ω. Determine the balance point of the bridge above if X and Y are interchanged.
(a) 8.2 Ω, 40.6 cm
(b) 8.2 Ω, 60.4 cm
(c) 6.2 Ω, 60.4 cm
(d) 6.2 Ω, 39.6 cm