Self Induction

Q.

Define transformation ratio of a transformer.

Q. Work done by an external agent in rotating an electric dipole slowly from the position of stable equilibrium to unstable equilibrium in uniform electric field

Q.

Is a house AC or DC?

Q. Question 20
Three 2 $\Omega$ resistors, A, B and C, are connected as shown in the figure. Each of them dissipates energy and can withstand a maximum power of 18W without melting. Find the maximum current that can flow through the three resistors?

Q. A square current carrying loop of side a produced magnatic field at its centre is B .find magnatic moment of this loop in terms of B

Q.

Does current flow through an inductor?

Q.

The appliance which works on the principle of moments is

1. Pendulum clock

2. Beam balance

3. Spring balance

4. Balance wheel

Q.

Please send me all the formulas used in solving problems of magnetic effect of electric current with their derivation.

Q.

In a coil when current changes from $10\mathrm{A}$ to $2\mathrm{A}$ in time $0.1\mathrm{s}$, induced emf is $3.28\mathrm{V}$. What is self-inductance of the coil?

1. $4\mathrm{H}$

2. $0.4\mathrm{H}$

3. $0.04\mathrm{H}$

4. $5\mathrm{H}$

Q. The phenomenon in which a changing current in a coil induces an emf in itself is called.

1. Mutual induction
2. Self induction
3. magnetism

Q.

The change in magnetic flux due to the flow of an AC in a solenoid will generate a back emf in the same solenoid in a direction opposite to that applied to it. Name this phenomenon.

1. Hysteresis

2. Self Induction

3. Electromagnetic Induction

4. Mutual Induction

Q.

Consider an infinitely long current carrying cylindrical straight wire

1. $\frac{3}{2}$

2. $\frac{2}{3}$

3. $2$

4. $\frac{1}{2}$

Q.

A solenoid that is carrying current has magnetic field lines similar to that of ____.

1. a horse-shoe magnet

2. a bar magnet

3. any current carring conductor

4. a spherical magnet

Q.

Changing a current in a coil produces EMF in the same coil. This phenomenon is known as

1. Mutual induction

2. Self induction

3. Self conduction

4. mutual conduction

Q. 5.A current of 5 ampere flows along a thin wire shaped as shown in the figure the radius of the curved part of the wire is equal to one 20 mm and the angle 2x =90^° . find the magnetic induction of the field at point O

Q.

Question 4
A current of 1 A is drawn by a filament of an electric bulb. Number of electrons passing through a cross-section of the filament in 16 seconds would be roughly

(a) ${10}^{20}$
(b) ${10}^{16}$
(c) ${10}^{18}$
(d) ${10}^{23}$​​​​​​​

Q.

The magnetic field associated with a current carrying straight conductor is in anticlockwise direction. If the conductor was held along east - west direction what will be the direction of current through it ? Also state the rule which is used to find the direction of current in this case

Q. ntA: Voltage across a resistor decreases in the direction of current and increases opposite to the direction of current.n ntR: Voltage drop or gain across a capacitor depends on the direction of current.n ntn ntExplain the correct reason as well as how reason is incorrect.n ntn

Q.

In self induction, ___.

1. an emf is induced because of varing magnetic field due to the flow of an AC through the solenoid
   

2. the flow of a direct current changes the magnetic flux associated with the coil

3. an emf is generated in direction opposite to applied emf

4. the flow of an alternating current does not change the magnetic flux associated with the coil

Q. An electric bulb of $100W-300V$ is connected with an $AC$ supply of $500V$ and $\frac{150}{\pi }Hz$ The required inductance to save the electric bulb is:

1. $2H$
2. $\frac{1}{2}H$
3. $4H$
4. $\frac{1}{4}H$

Q. Question 11
A student carries out an experiment and plots the V-I graph of three samples of nichrome wire with resistances R1, R2 and R3 respectively (Figure). Which of the following is true?


(a) R1 = R2 = R3
(b) R1 > R2 > R3
(c) R3 > R2 > R1
(d) R2 > R3 > R1

Q.

The electric field in a region of space is given by $E=5\hat{i}+2\hat{j}N/C$. The flux of $E$ due to this field through an area $1m^2$ lying in the $y-z$ plane, in SI units is?

Q.

Explain sign convention for amperes law.

Q. 63.A long straight wire carrying current I1 is placed in the plane of a Ribbon carrying current I2 parallel to the wire. The width of the ribbon in b. The straight conductor is placed at a distance a from the nearer edge of the ribbon. Find the force of attraction per unit length between the two?

Q.

The unit of self-inductance of a coil is?

Q. A self inductance coil has a resistance of $31.4\Omega$ and a self inductance of $17mH$. The frequency of ac at which the impedance is double the resistance is:

1. $5000Hz$
2. $500Hz$
3. $50Hz$
4. $250Hz$

Q.

How will you find the magnetic polarity of a solenoid without using a magnetic needle?

Q. The change in magnetic flux due to the flow of an AC in a solenoid generates a back emf in the same solenoid in a direction opposite to that applied to it. Name this phenomenon.

1. Mutual Induction
2. Hysteresis
3. Self Induction
4. Electromagnetic Induction

Q. 25.The inner wire of a straight coaxial cable has radius a while the outer wire has radii 3a and 5a. The cable carries equal and opposite currents of magnitude i (distributed uniformly across the cross-section) on the inner and outer wires (see figure).

Q. Two lamps, one rated 100 w and 220 V and the other 200 w and 220 V are connected in series and in parallel to the electric main supply of 220 V. Find the current drawn in each case.