The supply voltage to a room is 120 V. The resistance of the lead wires is 6 . A 60 W bulb is already switched on. What is the decrease of voltage across the bulb, when a 240 W heater is switched on in parallel to the bulb?
10.04 Volt
Zero Volt
2.9 Volt
13.3 Volt
Need details on this question
If and be the threshold wavelength and wavelength of incident light, the velocity of photoelectron ejected from the metal surface is :
As discussed in the concept
Photoelectric Effect 
 wherein
where
m is the mass of the electron
u is the velocity associated with the ejected electron.
h is plank’s constant.
v is frequency of photon,
v_{0}^{ }is threshold frequency of metal.
Hence the correct option is 3
Option 1)
Option 2)
Option 3)
Option 4)
Chloro compound of Vanadium has only spin magnetic moment of 1.73 BM. This Vanadium chloride has the formula :
(at. no. of V=23)
VCl_{2}
VCl_{4}
VCl_{3}
VCl_{5}
As discussed in
Magnetic Quantum Number (m) 
It gives information about the spatial orientation of the orbital with respect to standard set of coordinate axis.

The value of magnetic moment is 1.73 BM
where n is the number of unpaired electrons
After calculation n = 1
To obtain one unpaired electron V should be tetrapositive ion and the formula of its chlorid should be
Option 2 is correct
Option 1)
VCl_{2}
Incorrect option
Option 2)
VCl_{4}
Correct option
Option 3)
VCl_{3}
Incorrect option
Option 4)
VCl_{5}
Incorrect option
Resistance of a given wire is obtained by measuring the current flowing in it and the voltage difference applied across it. If the percentage errors in the measurement of the current and the voltage difference are 3% each, then error in the value of resistance of the wire is
6%
zero
1%
3%
As discussed in
Ohm's Law 
Current flowing through the conductor is directly proportional to the Potential difference accross two ends .
 wherein
unit 
Electric Resistance
Percentage error in is
Option 1)
6%
This option is correct.
Option 2)
zero
This option is incorrect.
Option 3)
1%
This option is incorrect.
Option 4)
3%
This option is incorrect.
This question has Statement I and Statement II. Of the four choices given after the Statements, choose the one that best describes the two Statemens.
Statement  I : Higher the range, greater is the resistance of ammeter.
Statement  II : To increase the range of ammeter,additional shunt needs to be used across it.
Statement  I is false, Statement  II is true.
Statement  I is true, Statement  II is true, Statement  II is the correct explanation of Statement  I.
Statement  I is true, Statement  II is true, Statement  II is not the correct explanation of Statement  I.
Statement  I is true, Statement  II is false.
As discussed in
Required shunt 
 wherein
Current through galvanometer
The answer follows from basic Principle of stunt and its use to make an ammeter:
Option 1)
Statement  I is false, Statement  II is true.
This option is correct.
Option 2)
Statement  I is true, Statement  II is true, Statement  II is the correct explanation of Statement  I.
This option is incorrect.
Option 3)
Statement  I is true, Statement  II is true, Statement  II is not the correct explanation of Statement  I.
This option is incorrect.
Option 4)
Statement  I is true, Statement  II is false.
This option is incorrect.
A 10 V battery with internal resistance and a 15V battery with internal resistance are connected in parallel to a voltmeter (see figure). The reading in the voltmeter will be close to :
11.9 V
12.5 V
13.1 V
24.5 V
As we discussed in
In closed loop 
 wherein
Current in the circuit
Reading of the voltmeter
Option 1)
11.9 V
The option is incorrect
Option 2)
12.5 V
The option is incorrect
Option 3)
13.1 V
The option is correct
Option 4)
24.5 V
The option is incorrect
A 3 olt battery with negligible internal resistance is connected in a circuit as shown in the figure. The current I i n the circuit will be
as discussed in
Parallel Grouping 
Potential  Same
Current  Different
 wherein
Option 1)
This option is incorrect.
Option 2)
This option is correct.
Option 3)
This option is incorrect.
Option 4)
This option is incorrect.
Two electric bulbs marked 25 W220 V and 100 W  220 V are connected in series to a 440 V supply .Which of the bulbs will fuse?
both
100W
25 W
neither
As discussed in:
Series Grouping 
Potential  Different
Current  Same
 wherein
Similarly,
The current flowing through the circuit
After solving this, we get
Thus the bulb rated 25W220V will fuse.
both
Option 2)100W
Option 3)25 W
Option 4)neither
Three capacitances, each of 3 F, are provided. These cannot be combined to provide the resultant capacitance of :
3
The magnitude of the average electric field normally present in the atmosphere just above the surface of the Earth is about
150 N/C, directed inward towards the center of the Earth. This gives the total net surface charge carried by the Earth to be:
+670 kC
 670 kC
 680 kC
+ 680 kC
As we discussed in the concept
Infinite Plane parallel sheets of charge 
If
and
and

Electric Field E = 150 N/C
Total surface charge carried by earth q= ?
As electric field is directed inwards, hence,
Option 1)
+670 kC
Option 2)
 670 kC
Option 3)
 680 kC
Option 4)
+ 680 kC
In the given circuit diagram when the current reaches steady state in the circuit, the charge on the capacitor of capacitance C will be :
As we discussed in concept
where in
at steady state there is no current through r1
Q=
Option 1)
Option 2)
Option 3)
Option 4)
The gap between the plates of a parallel plate capacitor of area A and distance between plates d, is filled with a dielectric whose permittivity varies linearly from at one plate to at the other. The capacitance of capacitor is :
As we discussed in
If K filled between the plates 
 wherein
Option 1)
Option 2)
Option 3)
Option 4)
The electric field in a region of space is given by, where E_{0}=100 N/C. The flux of this field through a circular surface of radius 0.02 m parallel to the YZ plane is nearly :
0.125 Nm^{2}/C
0.02 Nm^{2}/C
0.005 Nm^{2}/C
3.14 Nm^{2}/C
As we discussed in
Electric field \vec{E} through any area \vec{A} 
 wherein
New flux
where
Option 1)
0.125 Nm^{2}/C
Option 2)
0.02 Nm^{2}/C
Option 3)
0.005 Nm^{2}/C
Option 4)
3.14 Nm^{2}/C
A spherically symmetric charge distribution is characterised by a charge density having the following variation :
for r< R
Where r is the distance from the centre of the charge distribution and is a constant. The electric field at an internal point (r < R) is :
As we discussed in comcept
If P lies inside 

where
=
=
Option 1)
Option 2)
Option 3)
Option 4)
A parallel plate capacitor is made of two plates of length l, width w and separated by distance d. A dielectric slab (dielectric constant K) that fits exactly between the plates is held near the edge of the plates. It is pulled into the capacitor by a force where U is the energy of the capacitor when dielectric is inside the capacitor up to distance x (See figure). If the charge on the capacitor is Q then the force on the dielectric when it is near the edge is :
As we discussed in concept
If K filled between the plates 
 wherein
Option 1)
Option 2)
Option 3)
Option 4)
A cone of base radius R and height h is located in a uniform electric field parallel to its base. The electric flux entering the cone is :
As we discussed in the concept
Electric field \vec{E} through any area \vec{A} 
 wherein
Area of facing =
Option 1)
Option 2)
Option 3)
Option 4)
This question has statement 1 and statement 2. Of the four choices given after the statements, choose the one that best describes the two statements.
An insulating solid sphere of radius R has a uniformly positive charge density . As a result of this uniform charge distribution there is a finite value of electric potential at the centre of the sphere, at the surface of the sphere and also at a point out side the sphere. The electric potential at infinity is zero.
Statement 1 : When a charge q is taken from the centre to the surface of the sphere, its potential energy changes by
Statement 2 : The electric field at a distance r(r < R) from the centre of the sphere is
Statement 1 is true, Statement 2 is true, Statement 2 is not the correct explanation for statement 1.
Statement 1 is true, Statement 2 is false
Statement 1 is false, Statement 2 is true
Statement 1 is true, Statement 2 is the correct explanation for statement 1
As we discussed in
If P lies at centre r = 0 
i.e

Potential at the centre of the sphere,
Potential at the surface of the sphere,
When a charge q is taken from the centre to the surface, the change in potential energy is
Statement 1 is false. Statement 2 is true.
Option 1)
Statement 1 is true, Statement 2 is true, Statement 2 is not the correct explanation for statement 1.
Option 2)
Statement 1 is true, Statement 2 is false
Option 3)
Statement 1 is false, Statement 2 is true
Option 4)
Statement 1 is true, Statement 2 is the correct explanation for statement 1
In a uniformly charged sphere of total charge Q and radius R the electric field E is plotted as a function of distance from the centre. The graph which would correspond to the above will be :
: For uniformly charged sphere
As we discussed in
Graph   wherein
The variation of E with distance r from the centre is as shown.
Option 1)
Option 2)
Option 3)
Option 4)
Two capacitors C_{1} and C_{2} are charged to 120 V and 200 V respectively. It is found that by connecting them together the potential of each one can be made zero. Then :
9C_{1} = 4C_{2}
5C_{1} = 3C_{2}
3C_{1} = 5C_{2}
3C_{1} + 5C_{2} = 0
As we discussed in
Parallel Grouping 
 wherein
Option 1)
9C_{1} = 4C_{2}
Option 2)
5C_{1} = 3C_{2}
Option 3)
3C_{1} = 5C_{2}
Option 4)
3C_{1} + 5C_{2} = 0
Two charges, each equal to q, are kept at on the  axis. A particle of mass m and charge is placed at the origin. If charge is given a small displacement  axis,the net force acting on the particle is proportional to :
As we discussed in
Magnitude of the Resultant force 
 wherein
Option 1)
Option 2)
Option 3)
Option 4)