Electric Current
Trending Questions
Q. Q:- If 50 joule of work must be done to move an electric charge of 2 C from a point, where potential is -10V to another point where potential is V volt. Then, the value of V is 1. 5V 2. +15
Q. if 20 J work has to be to done to move an electric charge of 4 C from a point where potential is 10 volt to another point where potential is V volt, find value of V
Q. find the number of electron that should be removed from coin so that it acquires a charge of10^{-6} coulom
Q. Some positive charge is given to a conductor. Then its potential
- is maximum at surface
- is maximum at centre
- remains same through out the conductor
- is maximum somewhere between surface and centre
Q. Two conductors are made of the same material and have the same length. Conductor A is a solid wire of diameter 1 mm. Conductor B is a hollow tube of outer diameter 2 mm and inner diameter 1 mm.
Find the ratio of resistance RA to RB.
Find the ratio of resistance RA to RB.
Q. A constant voltage is applied between the two ends of a uniform metallic wire. Some heat is developed in it. The heat developed is doubled if
- both the length and the radius of the wire are halved
- the length of the wire is doubled
- the radius of the wire is doubled
- both the length and the radius of the wire are doubled
Q. 13.two points having charges q1 and q2 are placed at the coordinates a, 0, 0 and 0, b, 0 respectively.find out the electric feild intensity of a thrid point charge placed at 0, 0, c due to those two charges.
Q.
The electrical resistivity of silver is . What will be the resistance of a silver wire of length and cross-sectional area ?
Q. charge of 10micro coulomb is placed at the origin of x-y coordinate system. The potential difference between two points (0, a) and (a, 0) in volt will be
Q.
A positively charged ball is brought close to an electrically neutral isolated conductor. The conductor is then grounded while the ball is kept close.If the conductor is charged positively, charged negatively, or neutral if
(a) the ball is first taken away and then the ground connection is removed?
(b) the ground connection is first removed and then the ball is taken away?
Q. A wire of area of cross-section 3.0 mm2 and natural length 50 cm is fixed at one end and a mass of 2.1 kg is hung from the other end. Find the elastic potential energy stored in the wire in steady state. Young’s modulus of the material of the wire =1.9×1011N/m2. Take g=10m/s2
- 1.96×10−5 J
- 1.93×10−4 J
- 3.89×10−4 J
- 2.05×10−5 J
Q. Two conductors A and B each of cross-section area 5 cm2 are connected in series. Variation of temperature (in ∘C) along the length (in cm) is as shown in the figure. If thermal conductivity of A is 200 J/m s∘C and thermal conductivity of B is K (in J/m S∘C), then find √K8√3
Q. 86. The total number of electrons present in 96500 coulomb of electricity is
Q. The resistivity of a wire at 20^0C and 100^0C is 3Ω-m and 4Ω-m respectively. The resistivity of the wire at 0^0C is: Option 1: 11/4 ohm-m Option 2: 4/11 ohm-m Option 3: 3/4 ohm-m Option 4: 11/3 ohm-m
Q. A charge of 1 uc is given to one plate of a parallel plate capacitor of capacitance 0.1 μ F and a charge of 2is given to the other plate. Find the potential difference developed between the plates.
Q. A wire of cross-section area A, length L1, resistivity ρ1 and temperature coefficient of resistivity α1 is connected in series to a second wire of length L2, resistivity ρ2, temperature coefficient of resistivity α2 and the same area A, so that wires carry same current. Total resistance R is independent of temperature for small temperature change if (Thermal expansion effect is negligible)
- None
- α1=−α2
- ρ1L1α1+ρ2L2α2=0
- L1α1+L2α2=0
Q. Difference between cutoff voltage and stopping potential
Q. The circuit was in the shown state from a long time. Now, the switch S is closed. The charge that flows through the switch is
- 4003μC
- 100μC
- 50 μC
- 1003μC
Q. A metal wire of resistance 3Ω is elongated to make a uniform wire of double its previous length. This new wire is now bent and the ends joined to make a circle. If two points on this circle make an angle 60∘ at the centre, the equivalent resistance between these two points will be
- 52Ω
- 72Ω
- 53Ω
- 125Ω
Q. Two unequal bars in length and cross-section with thermal conductivities K1 and K2 are connected in series so that one end is maintained at θ1 ∘C and other end at θ2 ∘C. If the ratio of length of two bars is n1 and ratio of cross-sectional areas of two bars is n2, then find the value of n1/n2 for which temperature of the junction point is θ1+θ22 :
- K1K2
- K1+K2K2
- K1+K2K1
- K2K1+K2
Q. An electric fuse can prevent accidents arising from
- An overload but not due to short circuit.
- A short circuit but not due to overload.
- An overload as well as short circuit.
- Neither an overload nor a short circuit.
Q. The AC voltage across a resistance can be measured using
- a potentiometer
- a hot-wire voltmeter
- a moving-coil galvanometer
- a moving-magnet galvanometer
Q. Which one of the following is the property of a monochromatic, plane electromagnetic wave in free space ?
[1 Mark]
[1 Mark]
- Electric and magnetic fields have a phase difference of π2.
- The energy contribution of both electric and magnetic fields are equal.
- The direction of propagation is in the direction of →B×→E
- The pressure exerted by the wave is the product of its speed and energy density.
Q. If 1018 electrons are taken out every second from a body, then how much time is required to get a total charge of 0.1 C from it?
- 0.625 s
- 6.25 s
- 62.5 s
- 625 s
Q. Two conductors A and B of have their lengths in ratio 4:3, area of cross-section in ratio 1:2 and their resistivities in ratio 2:3 . What will be ratio of their resistances ?
Q. Calculate the electric field in a copper wire of cross-sectional area 2mm^2 carrying a current of 2 ampere; given that resistivity of copper wire is 1.7×10^-8 ohm m.
Q. 66. If the electron of hydrogen atom takes 3.2×10 to the power -17sec to complete one revolution, then how much current is constituted?
Q. AN INFINTE LONG THREAD CARRIES A CHARGE UNIFORMLY SPREAD OVER ITS LENGTH . IT IS BENT IN THE FORM AS SHOWN. IF THE CHARGE PER UNIT LENGTH IS LAMBDA , THE ELECTRIC FIELD AT POINT O IS
Q. As shown in figure, a metal rod of radius r1 is concentric with a metal cylindrical shell of radius r2 and length L. The space between rod and cylinder is tightly packed with material of resistivity ρ.A battery having terminal voltage V0 is connected as shown. Neglecting the resistance of rod and cylinder
- Effective resistance R between rod and cylinder will be ρln(r2r1)2πL
- Electric field at point P between rod and cylinder will be E=V0rln(r2r1)
- Current density at P will be J= J=V0ρrln(r2r1)
- Total current I will be 2πLV0ρln(r2r1)
Q. Two rods A and B of different materials are welded together as shown in figure. Their thermal conductivities are K1 and K2. The thermal conductivity of the composite rod will be
- K1+K22
- K1+K2
- 3(K1+K2)2
- 2(K1+K2)