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प्रश्न
Choose the correct alternative and rewrite the following:
What will happen to the current passing through a resistance, if the potential difference across it is doubled and the resistance is halved?
विकल्प
remains unchanged
becomes double
becomes half
becomes four times
उत्तर
becomes four times
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संबंधित प्रश्न
(a) Write the expression for the magnetic force acting on a charged particle moving with velocity v in the presence of magnetic field B.
Deduce the expression for the magnetic field at a point on the axis of a current carrying circular loop of radius ‘R’ distant ‘x’ from the centre. Hence, write the magnetic field at the centre of a loop.
A long straight wire in the horizontal plane carries a current of 50 A in north to south direction. Give the magnitude and direction of B at a point 2.5 m east of the wire.
A straight horizontal wire of mass 10 mg and length 1.0 m carries a current of 2.0 A. What minimum magnetic field B should be applied in the region, so that the magnetic force on the wire may balance its weight?
A conductor has three segments; two straights of length L and a semicircular with radius R. It carries a current I What is the magnetic field B at point P?
For a circular coil of radius R and N turns carrying current I, the magnitude of the magnetic field at a point on its axis at a distance x from its centre is given by,
B = `(μ_0"IR"^2"N")/(2("x"^2 + "R"^2)^(3/2))`
(a) Show that this reduces to the familiar result for field at the centre of the coil.
(b) Consider two parallel co-axial circular coils of equal radius R, and number of turns N, carrying equal currents in the same direction, and separated by a distance R. Show that the field on the axis around the mid-point between the coils is uniform over a distance that is small as compared to R, and is given by, B = `0.72 (μ_0"NI")/"R"` approximately.
[Such an arrangement to produce a nearly uniform magnetic field over a small region is known as Helmholtz coils.]
A magnetic field set up using Helmholtz coils is uniform in a small region and has a magnitude of 0.75 T. In the same region, a uniform electrostatic field is maintained in a direction normal to the common axis of the coils. A narrow beam of (single species) charged particles all accelerated through 15 kV enters this region in a direction perpendicular to both the axis of the coils and the electrostatic field. If the beam remains undeflected when the electrostatic field is 9.0 × 10–5 V m–1, make a simple guess as to what the beam contains. Why is the answer not unique?
In SI system, permeability has the units ______.
Correct unit of magnetic field is ______.
Assertion: Free electrons always keep on moving in a conductor even then no magnetic force act on them in magnetic field unless a current is passed through it.
Reason: The average velocity of free electron is zero.
- If v is parallel to B, then path of particle is spiral.
- If v is perpendicular to B, then path of particle is a circle.
- If v has a component along B, then path of particle is helical.
- If v is along B, then path of particle is a circle.
A charged particle would continue to move with a constant velocity in a region wherein ______.
- E = 0, B ≠ 0.
- E ≠ 0, B ≠ 0.
- E ≠ 0, B = 0.
- E = 0, B = 0.
Show that a force that does no work must be a velocity dependent force.
An electron enters with a velocity v = v0i into a cubical region (faces parallel to coordinate planes) in which there are uniform electric and magnetic fields. The orbit of the electron is found to spiral down inside the cube in plane parallel to the x-y plane. Suggest a configuration of fields E and B that can lead to it.
A 100 turn rectangular coil ABCD (in XY plane) is hung from one arm of a balance (Figure). A mass 500 g is added to the other arm to balance the weight of the coil. A current 4.9 A passes through the coil and a constant magnetic field of 0.2 T acting inward (in xz plane) is switched on such that only arm CD of length 1 cm lies in the field. How much additional mass ‘m’ must be added to regain the balance?
A long straight wire AB carries a current I. A particle (mass m and charge q) moves with a velocity `vec"v"`, parallel to the wire, at a distance d from it as shown in the figure. Obtain the expression for the force experienced by the particle and mention its directions.
A long straight conductor kept along X' X axis, carries a steady current I along the +x direction. At an instant t, a particle of mass m and charge q at point (x, y) moves with a velocity `vecv` along +y direction. Find the magnitude and direction of the force on the particle due to the conductor.
What is the relation between Tesla and Gauss?
