By applying the right hand thumb rule, the direction of magnetic field would be anti-clockwise around the direction of current. Thus, the magnetic field would be to point P and towards the plane of paper. At point Q, the direction of magnetic current would be from the conductor and away from the plane of paper. Since magnetic field is stronger near the conductor and weaker as we move away from the conductor, so the magnetic field would be stronger near point Q than near point P.

Given, P₁ = 250 W, P₂ = 1200 W,
t₁ = 1h = 3600 s, t₂ = 10 min = 600 s
\(\therefore\) Energy
Q₁ = P₁t₁ = 250 \(\times\)3600 = 900000 J = 900 kJ
and Q₂ = P₂t₂ = 1200 \(\times\) 600 = 720000 J = 720 kJ
Thus, TV set uses more energy.

Nichrome should be used as a heating element in an electric iron because its melting point is higher than iron and silver.

Electric fuse is used for protecting the circuits due to short circuiting or overloading of the circuits.

The magnetic field produced by a solenoid is similar to the bar magnet.

A galvanometer is an instrument that can detect the presence of a current in a circuit.

An electric motor.

When the total current drawn by all the appliances at a particular time exceeds the bearing capacity of that wire, the wires of the domestic wiring gets heated. This is called overloading.

(a) When the bar magnet is cut along its length, pole strength of each part is half the pole strength of the original magnet so its magnetic moment is also halved.
(b) In both cases, we get two magnets, each having north and south poles. When the bar magnet is cut transverse to its length, the pole strength of each part is same as that of the original magnet but its magnetic moment is halved because its length is halved.

An electric short circuit occurs when the insulation of wires is damaged or there is a fault in the appliance. Due to this, the live wire and neutral wire come in direct contact and the current in the circuit increases abruptly.

If two magnetic lines of force intersect each other, it would mean that there are two directions of the magnetic field at the point of intersection, which is not possible.

The resistance of 25 W lamp bulb has a higher value as compound to that of 50 W lamp bulb. Resistance of the 25 W lamp bulb. Resistance of the 25 W lamp bulb will be double of that of the 50 W lamp bulb.

Earth wire is used to provide a low resistance conducting path to any charge that gets leaked into the body of the appliance.

Electric power, p = \( \frac{V^{2}}{R}\), where R
V = Potential difference across the circuit
For 40 W bulb, 40 =\(\frac{V^{2}}{R_{1}0}\), where
R₄₀ = Resistance offered by the 40 W bulb 
For 60 W bulb, 60 =\(\frac{V^{2}}{R_{6}0}\) , where
R₄₀ = Resistance offered by the 60 W bulb
Therefore,  \(R_{10}=\frac{V^{2}}{40}\) and \(R_{60}=\frac{V^{2}}{60}\)  (as the voltage difference remains the same)
Therefore, R₄₀ > R₆₀
So, the 40 W bulb has a higher electrical resistance when in use. 

Thc cord of an electric heater has lesser resistance than its heating element. So, more heat is produced in the heating element than the cord and it glows.

The resistance of a conductor depends on following factors:
(i) Length of the conductor.
(ii) Area of cross-section of the conductor.
(iii) Nature of material of the conductor.

In a domestic circuit, parallel connection of devices is preferable for several reasons:
a. In series connection, if one of the devices is defective, if one of the devices is defective,     then the current of the entire circuit is cut off. As a result, all the devices stop working. In parallel connection, even if one device is defective, the others continue working.
b. In series connection, selective operation of devices is not possible, but this is not so in the case of parallel connection.
c. In series connection, the same current passes through all the devices, regardless of the fact that different devices require different values of current to operate. In parallel connection, different values of current can be obtained for different devices according to their requirements.

Electric cell or battery is a device that helps to maintain a potential difference across a conductor.

The major differences between an electric motor and generator are stated below:
Electric Motor:
1. It converts electrical energy into mechanical energy.
2. It needs electrical energy for its works.
3. They are used as water pumps, marble grinders etc.
Generator:
1. It converts mechanical energy into electrical energy
2. It needs mechanical energy for its working.
3. They are used as water pumps, marble grinders etc.
4. diesel generator, hydro-electric generator are the examples of it.

(i) Maxwell's right hand thumb rule:
It's a convenient way of finding the direction of magnetic field associated with a current carrying conductor. It states that, if you hold the current carrying straight wire in the grip of your right hand in such a way that the stretched thumb points in the direction of current, then the direction of the curl of the fingers will give the direction of the magnetic field. This rule is also called Maxwell's corkscrew rule.
(ii) Fleming's left hand rule:
The direction of force which acts on a current carrying conductor placed in a magnetic field is given by Fleming's left hand rule.
It states that, if the forefinger, thumb and middle finger of left hand are stretched mutually perpendicular to each other, such that the forefinger points along the direction of external magnetic field, middle finger indicates the direction of current, then the thumb points towards the direction of force acting on the conductor.
(iii) Fleming's right hand rule gives the direction of induced current in a coil due to it's rotation in a magnetic field. If the forefinger points in the directions of magnetic field, thumb in the direction of motion of the conductor, then the central finger points in the direction of current induced in the conductor.

(i) When the bar magnet is pushed into the coil, the galvanometer needle would show deflection.
(ii) Withdrawn from the coil, the galvanometer needle would show deflection.
(iii) When the bar magnet is kept stationary inside the coil, when the bar magnet galvanometer needle would show no deflection.

For electromagnetic induction, the coil and the magnet should be in relative motion. This can be ensured by any of the following two ways :
(a) The coil should be moved within a magnetic field.
(b) The magnet should be moved and coil can be kept static.

(i) The 5 Ω resistors are connected in series. Therefore, their effective resistance = (5 + 5) = 10 Ω
    The 10 Ω resistors are connected in series. Therefore, their effective resistance = (10 + 10) = 20 Ω
    Now these 10 Ω equivalent and 20 Ω equivalent are connected in parallel. Therefore, the equivalent resistance         (R_eq) will be:
     \(\frac { 1 }{ { R }_{ eq } } =\frac { 1 }{ { R }_{ 1 } } +\frac { 1 }{ { R }_{ 2 } } \)                   
     \(\frac { 1 }{ { R }_{ eq } } =\frac { 1 }{ 10 } +\frac { 1 }{ 20 } \)
     \(\frac { 1 }{ { R }_{ eq } } =\frac { 2+1 }{ 20 } \)
     \(\frac { 1 }{ { R }_{ eq } } =\frac { 20 }{ 3 } =6.76\Omega \)
(ii) Total Current = Total voltage / Total equivalent resistor 
                          =12 / 6.67
                          = 1.8 A.

It is given that: Voltage (V) = 2.50 V
Current (I) = 750 mA = 0.75 A
The bulb is lighted for 4 hours.
Thus,
(i) Power generated (P) = VI = 2.50\(\times\) 0.75 = 1.87 W
(ii) Resistance (R) = \(\frac { V }{ I } =\frac { 2.5 }{ 0.75 } =3.33\Omega \)
(iii) Energy consumed in 4 hours = Power\(\times\)Time = P\(\times\)t =1.87\(\times\)4 = 7.48  Wh

(a) Ohm's Law states that at constant temperature, current flowing through a conductor is directly proportional to the       potential difference across its ends.

(a) Resistance is defined as the property of a conductor due to which it opposes the flow of current through it. The S.I. unit of resistance is Ohm \(\left( \Omega \right) \).
(b) (i) The resistance (R) of a conductor is related to its length (l) and area of cross section (A) as
          \(R=\frac { p\times l }{ A } \)  Where \(\rho \) is the resistivity of the conducting material.
Let R₁= Resistance of the original wire
      R₂= Resistance of the wire when its length is doubled
I₁= Length of original wire
l₂= Length of original wire when doubled
A₁= Area of the original wire
A₂= Area when it is halved 
Therefore,
 \({ R }_{ 1 }=\frac { P\times { l }_{ 1 } }{ { A }_{ 1 } } \quad \quad ---\quad (1)\\ { R }_{ 2 }=\frac { P\times { l }_{ 2 } }{ { A }_{ 2 } } \quad \quad ---\quad (2)\)
Dividing equation (1) and (2) by equation (1), we obtain
\(\frac { { R }_{ 1 } }{ { R }_{ 2 } } =\frac { { l }_{ 1 } }{ { l }_{ 2 } } \times \frac { { A }_{ 1 } }{ { A }_{ 2 } } \quad ---\quad (3)\)
It is given that:
\({ l }_{ 1 }=2l_{ 1 }\quad and\quad { A }_{ 2 }=\frac { 1 }{ 2 } { A }_{ 1 }\\ \)
Putting these values in equation (3), we obtain
R₂=4R₁
Hence, the resistance of the wire will be 4 times of the original value.
(ii) The resistivity will not change on stretching the wire. Resistivity is the property of the conducting material. It does not depend on the dimension of the wire. As materials of both the wires are the same, the resistivity will not change.

(a)
  
(b) Electric current flowing through a bulb = \(\frac { Power\quad of\quad the\quad bulb }{ Voltage\quad across\quad the\quad bulb } \)
\(i.e.,\quad I=\frac { P }{ V } \)
Therefore, \({ I }_{ 60 }=\frac { 60W }{ 220V } =\frac { 3 }{ 11 } A\quad and\quad { I }_{ 40 }=\frac { 40W }{ 220V } =\frac { 2 }{ 11 } A\)
Therefore, total current flowing through the circuit  \(={ I }_{ 60 }+{ I }_{ 40 }=\frac { 3 }{ 11 } +\frac { 2 }{ 11 } =\frac { 5 }{ 11 } A=0.45A\)
(c) Total energy consumed = Power \(\times \) Time
      That is, E = P \(\times \) T
                      = (40W+60W)\(\times \)1h
                    = 100 Wh
                    = 0.1 kWh

(a) Since two \(8\Omega \) resistors are in parallel, their effective resistance (\({ R }_{ P }\)) is given by,
\(\frac { 1 }{ { R }_{ P } } =\frac { 1 }{ 8 } +\frac { 1 }{ 8 } +\frac { 1 }{ 4 } \) or \({ R }_{ P }=4\Omega \)
(b) Total resistance in the circuit
\(R=4\Omega +{ R }_{ P }=4\Omega +4\Omega =84\Omega \)
Current through the electric circuit
\(I=\frac { V }{ R } =\frac { 8V }{ 8\Omega } =1A\)
(c) The potential difference \(4\Omega \) resistor V
 I \(=IR=1\times 4=4V\) 
(d) Power dissipated in \(​​​​4\Omega \) resistor P=\({ (I) }^{ 2 }\)
\(R={ (1) }^{ 2 }(4)=4W\)
(e) There is no difference in the readings of ammeters \({ A }_{ 1 }\) and  \({ A }_{ 2 }\) as same current flows through all elements in a series circuit.

(a) An electromagnet is a device used to produce magnetic field with the help of electricity.
(b) An electromagnet is used for lifting heavy loads. It is also used in automatic door locking systems.
(c)
 
(d) A soft iron is used as a core in order to strengthen the magnetic field created by the electromagnet.

(a) Magnetic field is the region around a magnet in which a magnetic material experiences a force because of that magnet.
(b) The direction of magnetic field at a point is determined by using a magnetic compass. The direction along which the needle of a magnetic compass gets aligned indicates the direction of the magnetic field.
(c) A straight thick conducting wire is inserted normally through centre of a plane paper. Now, electric current is passed through the wire. When a small magnetic compass is placed on the paper, the magnetic needle of the compass gets aligned along a particular direction. The positions of the North Pole and South Pole are marked on the paper. Now, the magnetic needle is shifted to a new position such that its South Pole occupies the position previously occupied by its North Pole. Again, the positions of the North Pole and South Pole are marked. These steps are repeated over and over again and the marked points are joined to obtain the direction of the magnetic field generated by the current-carrying straight wire.
(d) The direction of magnetic field at the centre of a current of a current carrying loop is normal to the plane formed by the loop.

Magnetic Field Due to Circular Loop Current-Carrying Conductor:

In case of a circular current carrying conductor, the magnetic field lines would be in the form of concentric circles around every part of the periphery of the conductor. Since, magnetic field lines tend to remain closer when near the conductor, so the magnetic field would be stronger near the periphery of the loop. On the other hand, the magnetic field lines would be distant from each other when we move towards the centre of the current carrying loop. Finally, at the centre, the arcs of big circles would appear as a straight lines.
Magnetic field and number of turns of coil: Magnitude of magnetic field gets summed up with increase in the number of turns of coil. If there are 'n' turns of coil, magnitude of magnetic field will be 'n' times of magnetic field in case of a single turn of coil.

A number of resistors are said to be connected in series, if these are joined end to end and the same, current flows through each one of them when a potential difference is applied across the combination. If we connect ammeter first between the point A and R₁, then between R1 and R₂:R₂ and R₃ and lastly between R₃ and the point B; it is same as current.