Q.1.
The supply voltage to a room is $$120\ V$$. The resistance of the lead wires is $$6\ \Omega$$. A $$60W,120V$$ bulb is already switched on. What is the decrease of voltage across the bulb, when a $$240 W,120V$$ heater is switched on in parallel to the bulb?
-
0%
$$2.9$$ $$volt$$
-
0%
$$13.3$$ $$volt$$
-
0%
$$10.04$$ $$volt$$
-
0%
$$zero\ volt$$
Explanation
Q.2.
A $$220$$ volt, $$1000$$ watt bulb is connected across a $$110$$ volt mains supply. The power consumed will be.
-
0%
$$750$$ watt
-
0%
$$500$$ watt
-
0%
$$250$$ watt
-
0%
$$1000$$ watt
Q.3.
The resistance of a $$10m$$ long potentiometer wire is $$50\Omega$$. It is connected in series with a $$3V$$ battery and $$10\Omega$$ resistor. The potential difference between two points separated by distance $$40cm$$ is equal to ______
-
0%
$$0.02V$$
-
0%
$$0.1V$$
-
0%
$$0.06V$$
-
0%
$$1.2V$$
Explanation
Q.4.
If the figure shows a part of an electric circuit, then the current $$I$$ is
-
0%
$$1A$$
-
0%
$$3A$$
-
0%
$$2A$$
-
0%
$$4A$$
Explanation
Q.5.
If $${i}_{1}=3\sin{\omega t}$$ and $${i}_{2}=4\cos{\omega t}$$, then $${i}_{3}$$ is -
-
0%
$$5\sin{(\omega t+{53}^{o})}$$
-
0%
$$5\sin{(\omega t+{37}^{o})}$$
-
0%
$$5\sin{(\omega t+{45}^{o})}$$
-
0%
$$5\cos{(\omega t+{53}^{o})}$$
Q.6.
A solid spherical conducting shell has inner radius $$a$$ and outer radius $$2a$$. At the centre of the shell a point charge $$+Q$$ is located. What must be the charge of the shell be in order for the charge density on the inner and outer surfaces of the shell to be exactly equal?
-
0%
$$-5Q$$
-
0%
$$+3Q$$
-
0%
$$-4Q$$
-
0%
$$+4Q$$
Explanation
Q.7.
Consider a cube as shown in the fig-1; with uniformly distributed charge within its volume. The potential at one of its vertex P is $${V_0}$$.A cubical portion of half the size (half edge length) of the original cube is cut and removed as shown in the fig-Find the modulus of potential at the point P in the new structure.
-
0%
$${{7} \over 8}{V_0}$$
-
0%
$${{{V_0}} \over 2}$$
-
0%
$${{3{V_0}} \over 4}$$
-
0%
$${{{V_0}} \over 4}$$
Q.8.
The number of turns in th coil of an $$ac$$ generator is $$5000$$ and the area of the coil is $$0.25\ {m}^{2}$$. The coil is rotated at the rate of $$100$$ cycles/s in a magnetic field of $$0.2\ T$$. The peak value of emf generated is nearly:
-
0%
$$786\ kV$$
-
0%
$$440\ kV$$
-
0%
$$220\ kV$$
-
0%
$$157.1\ kV$$
Q.9.
A potentiometer has a wire of 100 cm length and its resistance is 10 ohms. It is connected in series with a resistance of 40 ohms and a battery of emf 2 V and negligible internal resistance. If a source of unknown emf E connected in the secondary is balanced by 40 cm length of potentiometer wire, the value of E is:
-
0%
0.2 V
-
0%
0.4 V
-
0%
0.08 V
-
0%
0.16 V
Q.10.
Refer to teh circuit shown. What will be the total power dissipation in the circuit if $$P$$ is the power dissipated in $${R}_{1}$$? It is given that $${R}_{2}=4{R}_{1}$$ and $${R}_{3}=12{R}_{1}$$
-
0%
$$4P$$
-
0%
$$7P$$
-
0%
$$13P$$
-
0%
$$17P$$
Q.11.
A potentiometer wire of $$10\ m$$ length and having a resistance of $$1\ ohm/m$$ is connected to an accumulator of emf $$2.2$$ volt and a high resistance box. To obtain a potential gradient of $$2.2mV/m$$, the value of resistance used from the resistance box is :-
-
0%
$$790\ ohm$$
-
0%
$$810\ ohm$$
-
0%
$$990\ ohm$$
-
0%
$$1000\ ohm$$
Q.12.
The temperature coefficient of resistance of wire is $$12.5 \times 10^{-4} / C^0$$. At 300K the resistance of the wire is 1 ohm. The temperature at which resistance will be 2 ohm is
-
0%
1154K
-
0%
1100K
-
0%
1400K
-
0%
1127K
Q.13.
For the following circuits, the potential difference between
X and Y in volt is $$\left( {{V_x} - {V_y}} \right)$$
-
0%
1
-
0%
-1
-
0%
2
-
0%
-2
Explanation
Q.14.
Write T against true and F against false in the statements.
A charged glass road attract a charged plastic straw
A charged glass road attract a charged plastic straw
-
0%
True
-
0%
False
Q.15.
If current $$I_1 = 3A$$ sin $$\omega t$$ and $$I_2 = 4A$$ cos $$\omega t$$, then $$I_3$$ is :
-
0%
$$5A sin (\omega t + 53^0)$$
-
0%
$$5A sin (\omega t + 37^0)$$
-
0%
$$5A sin (\omega t + 45^0)$$
-
0%
$$5A sin (\omega t + 30^0)$$
Q.16.
In the circuit shown, the current in the $$1
ohm$$ resistor is:
ohm$$ resistor is:
-
0%
$$ 0.13A, $$ from Q to P
-
0%
$$0.13A, $$ from P to Q
-
0%
$$ 1.3A, $$ from P to Q
-
0%
$$ 0A, $$
Q.17.
In the diagram shown $$P$$ is a point negative charge. It's weight is balanced by the electric force due to the fixed very long wire. The equilibrium of the particle is
-
0%
Stable for vertical displacements
-
0%
Neutral for vertical displacements
-
0%
Stable for horizontal displacements (parallel to the wire)
-
0%
Neutral for horizontal displacements (parallel to the wire)
Q.18.
Find the potentials of points A and B:-
-
0%
$$V_A = + 10 \ V; V_B = 0 \ V$$
-
0%
$$V_A = + 7.5 \ V; V_B = - 2.5 \ V$$
-
0%
$$V_A = + 2.5 \ V; V_B = - 7.5 \ V$$
-
0%
$$V_A = + 0 \ V; V_B = - 10 \ V$$
Explanation
Q.19.
If the resistance in the circuit is increased four times by keeping the potential difference the same, the current in the circuit is ___________.
-
0%
Remains same
-
0%
Four times
-
0%
One fourth
-
0%
Half
Q.20.
$$AB$$ is part of a circuit as shown, that absorbs energy at a rate of $$50 \ W$$. $$E$$ is an electromotive force device that has no internal resistance.
-
0%
Potential difference across $$AB$$ is $$48 V$$
-
0%
Electromotive force device is $$48 V$$.
-
0%
Point $$B$$ is connected to the positive terminal of $$E$$.
-
0%
Rat of conversion from electrical to chemical energy is $$48 W$$ in device $$E$$.
Q.21.
Charges $$ 25Q,9Q$$ and $$Q$$ are placed at point $$ABC$$ such that $$AB=4m$$, $$BC=3m$$ and angle between $$AB$$ and $$BC$$ is $$90^\circ$$. then force on the charge $$C$$ is:
-
0%
Zero
-
0%
$$\frac{q^2}{{\pi { \in _0}\sqrt 5 }}$$
-
0%
$$\frac{{2{Q^2}}}{{\pi { \in _0}}}$$
-
0%
$$\frac{{5{Q^2}}}{{4\pi { \in _0}}}$$
Explanation
Q.22.
The $$V-I$$ graph for a conductor at temperature $$T_{1}$$ and $$T_{2}$$ are as shown in figure. The term $$(T_{2}-T_{1})$$ is proportional to:
-
0%
$$\cos 2\theta$$
-
0%
$$\sin 2\theta$$
-
0%
$$\cot 2\theta$$
-
0%
$$\tan 2\theta$$
Q.23.
An electric motor operates on a $$50 \ V$$ supply and a current of $$1 \ A $$. If the efficiency of the motion is $$30 \ \%$$, what is the resistance of winding of motion ?
-
0%
$$35 \ \Omega$$
-
0%
$$4 \ \Omega$$
-
0%
$$2.9 \ \Omega$$
-
0%
$$3.1\ \Omega$$
Q.24.
Potentiometer wire Pq of length 1m is connected to a standard cell $$ E_1 $$ Another cell of E2 of emf1.02v/s connected as shown in the circuit diagram with a resistance 'r' and with a switch 's' . With the switch S open, null position is obtained at a distance of 51 cm from p,Calculate
-
0%
emf of the cell.
-
0%
Potential gradient of the wire.
-
0%
When switch S is closed, will null point moves towards p or Q?
-
0%
insufficient data
Q.25.
Potentiometer is based on
-
0%
Deflection method
-
0%
Zero deflection method
-
0%
Both (a) and (b)
-
0%
None of these
Q.26.
Two cells each of electromotive force $$E$$ and internal resistance $$r$$ are concerned in parallel across the resistance $$R$$. The maximum energy given to the resistor per second if:
-
0%
$$R = \dfrac{r}{2}$$
-
0%
$$R = r$$
-
0%
$$R = 2r$$
-
0%
$$R = 0$$
Q.27.
The wire of potentiometer has resistance $$4 \Omega$$ and length $$1 m$$. It is connected to a coil of electromotive force $$2$$ volt and internal resistance $$1 \Omega$$. If a cell of electromotive force $$1.2$$ volt is balanced by it, the balancing length will be:
-
0%
$$90 \ cm$$
-
0%
$$60 \ cm$$
-
0%
$$50 \ cm$$
-
0%
$$75 \ cm$$
Q.28.
For comparing the electromotive force of two cells with a potentiometer, a standard cell is used to develop a potential gradient along the wire. Which of the following possibilities would make the experiment unsuccessful?
-
0%
The electromotive force system of the standard cell is larger than the $$E$$ electromotive force system of the two cells.
-
0%
The diameter of the wires is the same and uniform throughout
-
0%
The number of wires is ten
-
0%
The electromotive force of the standard cell is smaller than the electromotive force of the two cells.
Q.29.
Two identical batteries, each of electromotive force $$2 V$$ and internal resistance $$r = 1 \Omega$$ are connected as shown. The maximum power that can be developed across $$R$$ using these batteries is:
-
0%
$$2 W$$
-
0%
$$3.2 W$$
-
0%
$$8,2 W$$
-
0%
$$4 W$$
Q.30.
$$n$$ identical cells each of electromotive force $$e$$ and internal resistance $$r$$ are connected in series of this combination. The current through $$V$$ is:
-
0%
$$\frac{{2e}}{n}$$
-
0%
$$\dfrac{n \space e}{nR + r}$$
-
0%
$$\dfrac{e}{R + nr}$$
-
0%
$$\dfrac{n \space e}{R + r}$$
Q.31.
A resistor of resistance $$1000 \Omega$$ is connected to an AC source $$E=220 V sin(100 \pi rad/s$$ . the power consumed by resistor is
-
0%
$$48.4 W$$
-
0%
$$24.2 W$$
-
0%
$$12.1 W$$
-
0%
ZERO
Q.32.
For an AC Circuit, the potential difference and current are given by $$V=10\sqrt { 2 } \sin { \omega t } $$ (inV) and $$I=2\sqrt { 2 } \cos { \omega t }$$ (in A) respectively.The power dissipated in the instrument is:
-
0%
$$20W$$
-
0%
$$40W$$
-
0%
$$40\sqrt { 2 }W$$
-
0%
Zero
Q.33.
Eight resistances each of resistance $$5\Omega $$ are connected in the circuit as shown in figure. The equivalent resistance between $$A$$ and $$B$$ is
-
0%
$$\dfrac{8}{3}\Omega $$
-
0%
$$\dfrac{16}{3}\Omega $$
-
0%
$$\dfrac{15}{7}\Omega $$
-
0%
$$\dfrac{19}{2}\Omega $$
Q.34.
Two resistances of $$400\Omega$$ and $$800\Omega$$ are connected in series with a $$6$$ volt battery of negligible internal resistance. A voltmeter of resistance $$10,000\Omega$$ is used to measure the potential difference across $$400\Omega$$. The error in the measurement of the potential difference in volts approximately is :
-
0%
$$0.01$$
-
0%
$$0.02$$
-
0%
$$0.03$$
-
0%
$$0.05$$
Q.35.
If $${i_1} = 3\sin \omega t\,and\,{i_2} = 4\cos \omega t$$, then $$i_3$$ is
-
0%
$$5\sin \left( {\omega t + {{53}^ \circ }} \right)$$
-
0%
$$5\sin \left( {\omega t + {{37}^ \circ }} \right)$$
-
0%
$$5\sin \left( {\omega t + {{45}^ \circ }} \right)$$
-
0%
$$5\cos \left( {\omega t - {{53}^ \circ }} \right)$$
Q.36.
In wheatstone's bridge $$P = 9$$ ohm, $$ R = 4 $$ ohm and $$ S = 6 $$ ohm. How much resistance must be put in parallel to the resistance S to balance the bridge?
-
0%
$$24$$ ohm
-
0%
$$13.5$$ ohm
-
0%
$$7.2$$ ohm
-
0%
$$18.7$$ ohm
Explanation
Q.37.
A circular coil of area $$8{m^2}$$ and number of turns 20 is placed in a magnetic field of 2T with its plane perpendicular to it. It is rotated with an angular velocity of 20rev/s about its natural axis. The emf induced is
-
0%
$$400 V$$
-
0%
$$800\pi V$$
-
0%
$$Zero$$
-
0%
$$400\pi V$$
Q.38.
In the following diagram, the deflection in the galvanometer in a potentiometer
circuit is zero, then
circuit is zero, then
-
0%
$${E_1} > {E_2}$$
-
0%
$${E_2} > {E_1}$$
-
0%
$${E_1} = {E_2}$$
-
0%
$${E_1} + {E_2} = E$$
Explanation
Q.39.
At what temperature will the resistance of a copper wire become three times its value at $$0^{0}$$ C? [Temperature coefficient of resistance for copper = $$4\times 10^{-3}per^{0}C$$]:-
-
0%
$$500^{0}C$$
-
0%
$$450^{0}C$$
-
0%
$$600^{0}C$$
-
0%
None of these
Q.40.
Taking the electric charge 'e' and permittivity $$\epsilon$$ .use dimensional analysis to determine the correct expression for Wp. Where Wp $$\rightarrow $$ angular frequency N $$\rightarrow $$ number of density of free electron, m $$\rightarrow $$ mass
-
0%
$$\sqrt{\dfrac{Ne}{m\epsilon}}$$
-
0%
$$\sqrt{\dfrac{me}{N\epsilon}}$$
-
0%
$$\sqrt{\dfrac{Ne^2}{m\epsilon}}$$
-
0%
$$\sqrt{\dfrac{Ne^3}{m\epsilon}}$$
Q.41.
Wattless current in the circuit is
-
0%
3.75 A
-
0%
5 A
-
0%
2.1 A
-
0%
zero
Q.42.
Three resistances $$R_1,R_2$$ & $$R_3$$ $$(R_1> R_2> R_3)$$ are connected in series. If current $$I_1,I_2$$ & $$I_3$$ respectively is flowing through them, the correct relation will be
-
0%
$$I_1=I_2=I_3$$
-
0%
$$I_1> I_2> I_3$$
-
0%
$$I_1< I_2< I_3$$
-
0%
$$I_1> I_2< I_3$$
Explanation
Q.43.
The inductance of a coil is $$L = 10 H$$ and resistance $$R = 5 \Omega$$. If applied voltage of battery is $$10 V$$ and it switches off in $$1$$ millisecond, find induced electromotive force of inductor.
-
0%
$$2 \times 10^4 V$$
-
0%
$$1.2 \times 10^4 V$$
-
0%
$$2 \times 10^{-4} V$$
-
0%
None of these
Q.44.
If the circuit shown in the figure, the internal resistance of the battery is $$1.5\Omega$$ and $${V}_{p}$$ and $${V}_{Q}$$ are potentials at $$P$$ and $$Q$$ respectively. What is the potential difference between the points $$P$$ and $$Q$$
-
0%
$$Zero $$
-
0%
$$4\ volt\ \left({V}_{p}>{V}_{Q}\right)$$
-
0%
$$4\ volt\ \left({V}_{Q}>{V}_{P}\right)$$
-
0%
$$2.5\ volt\ \left({V}_{Q}>{V}_{P}\right)$$
Q.45.
In the given figure, if the heat flowing through the 5 $$ohm$$ resistance is 10 calorie then how much heat is flowing through the 4 $$ohm$$ resistance ?
-
0%
1 calorie
-
0%
2 calorie
-
0%
3 calorie
-
0%
4 calorie
Q.46.
An electron is rotating around an infinite positive linear charge in a circle of radius 0.1 m, if the linear charge density is $$ 1 \mu C/m, $$ then the velocity of electron in m/s will be
-
0%
$$ 0.562 \times 10^7 $$
-
0%
$$ 5.62 \times 10^7 $$
-
0%
$$ 562 \times 10^7 $$
-
0%
$$ 0.0562 \times 10^7 $$
Explanation
Q.47.
A $$3hp$$ motors requires $$2.4 kw$$ to drive it; its efficiency is about:
-
0%
$$90$$%
-
0%
$$75$$%
-
0%
$$60$$%
-
0%
$$50$$%
Q.48.
For which of the following substances the resistance decreases with the decrease in temperature:
-
0%
Germanium
-
0%
Silicon
-
0%
Silver
-
0%
None
Q.49.
The temperature coefficient of resistance of a wire is 0.00125 per degree celcius. At 300 K its resistance of the wire is 2 ohms. The temperature when resistance doubles is :-
-
0%
1154 K
-
0%
1100 K
-
0%
600 K
-
0%
1400 K
Q.50.
The name of the instrument which records electrical energy consumed by customer is
-
0%
Ampere-hour meter
-
0%
Watt-hour meter
-
0%
Var-hour meter
-
0%
Volt-ampere meter