The current (I) in the inductance is varying with time according to the plot shown in a figure.

A coil of self -inductance L is connected in series with a bulb b and an AC source. Brightness of the bulb decreases when

• frequency of the AC source is decreases

• number of turns in the coil is reduced

• a capacitance of reactance X_c=X_L is  included in the same circuit

• a capacitance of reactance X_c=X_L is  included in the same circuit

A current loop in a magnetic field

• experiences a torque whether the field is uniform or non-uniform in all orientations

• can be in equilibrium in one orientations

• can be an equilibrium in two orientations, both the equilibrium states are unstable

• can be an equilibrium in two orientations, both the equilibrium states are unstable

The rate of increase of thermo - emf with temperature at the neutral temperature of a thermocouple

• is zero

• depends upon the choice of the two materials of the thermocouple

• is negtive

• is negtive

55.

The current i in a coil varies with time as shown in the figure. The variation of induced emf with time would be

• 
• 
• 
• 

If potential (in volts) in a region is expressed as V (x, y, z) = 6 xy-y +2 yz, the electric field (in N/C) at point (1,1,0) is 

A conducting circular loop is placed in a uniform magnetic field, B = 0.0025 T with its plane perpendicular to the loop. The radius of the loop is made to shrink at a constant rate of 1 mms^-1. The induced emf when the radius is 2 cm, is

• 2 πμ V

• πμ V

• πμ V/2

• πμ V/2

Which of the following statement is false or the properties of electromagnetic waves?

• Both electric and magnetic field vectors attain the maxima and minima at the same place and same time

• The energy in electromagnetic waves is divided equally between electric and magnetic  vectors

• Both electric and magnetic field vectors are parallel to each other and perpendicular to the direction of propagation of wave

• Both electric and magnetic field vectors are parallel to each other and perpendicular to the direction of propagation of wave

A condenser of capacity C is charged to a potential difference of V₁. The plates to the condenser are then connected to an ideal inductor of inductance L. The current through the inductor when the potential difference across the condenser reduces to V₂ is

The thermal emf E in volt of a certain thermocouple is found to vary with temperature difference θ in ^oC between the two junctions according to the relation

The neutral temperature for the thermocouple will be

• 450^o C

• 400^o C

• 225^o C

• 225^o C