Let and be the roots of equation
is equal to:
6
6
3
3
3
Let ABC be a triangle whose circumcentre is at P. If the position vectors of A, B, C
and P are
respectively, then the position vector of the orthocentre of this triangle, is :
https://www.youtube.com/watch?v=y30g2lfwv_c
If (10)^{9} + 2(11)^{1} (10)^{8} + 3(11)^{2} (10)^{7} +...... +10 (11)^{9} = k (10)^{9}, then k is equal to :
100
110
Use
Sum of n terms of a GP 
 wherein
first term
common ratio
number of terms
and
(10)^{9} + 2(11)^{1} (10)^{8} + 3(11)^{2} (10)^{7} +...... +10 (11)^{9} = k(10)^{9}
Take common 10^{9}
Subtract
Option 1)
100
Option 2)
110
Option 3)
Option 4)
In a large building, there are 15 bulbs of 40 W, 5 bulbs of 100 W, 5 fans of 80 W and 1 heater of 1 kW. The voltage of the electric mains is 220 V. The minimum capacity of the main fuse of the building will be :
8 A
10 A
12 A
14 A
As we have learned
In parallel Grouping 

Resistance of each bulb of 40 W
Resistance of 15 bulbs = 1210/15 = 242/3
Resistance of 100 W bulb =
Resistance of 5 such bulbs = 485/5
Resistance of fan = = 605
Resistance of 5 such fan = 605 /5
= 121
Resistance of heater =
Equivalent resistance
R = 484 / 25
Option 1)
8 A
Option 2)
10 A
Option 3)
12 A
Option 4)
14 A
In the circuit shown, current (in A) through the 50 V and 30 V batteries are, respectively :
2.5 and 3
3.5 and 2
4.5 and 1
3 and 2.5
As we discussed in
Cell 
The device which converts Chemical energy into electrical energy is known as electric cell.
Option 1)
2.5 and 3
Option 2)
3.5 and 2
Option 3)
4.5 and 1
Option 4)
3 and 2.5
A d.c. main supply of e.m.f. 220 V is connected across a storage battery of e.m.f. 200 V through a resistance of 1. The battery terminals are connected to an external resistance ‘R’. The minimum value of ‘R’, so that a current passes through the battery to charge it is :
zero
Option 1)
Option 2)
Option 3)
Option 4)
zero
In the circuit shown, the current in the 1 resistor is :
1.3 A ,from P to Q
0 A
0.13 A ,from Q to P
0.13 A ,from P to Q
answer is option 3)0.13A from Q to P
In the electric network shown, when no current flows through the resistor in the arm EB, the potential difference between the points A and D will be :
3V
4V
5V
6V
The potential difference can be calculated via following method:
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)