Advertisements
Advertisements
प्रश्न
Show that a force that does no work must be a velocity dependent force.
उत्तर
To show that a force that does no work must be a velocity-dependent force, then we have to assume that work done by force is zero. As shown by the equation below:
`dW = vecF * vec(dl) = 0`
We can write, `vec(dl) = vecv dl`, but `dt ≠ 0`
⇒ `vecF * vecv dt = 0`
⇒ `vecF * vecv = 0`
So we can say that force F must be velocity dependent, this implies that angle between F and v is 90°. If the direction of velocity changes, then direction of force will also change.
APPEARS IN
संबंधित प्रश्न
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.
Explain the term hysteresis
Two wires carrying equal currents i each, are placed perpendicular to each other, just avoiding a contact. If one wire is held fixed and the other is free to move under magnetic forces, what kind of motion will result?
The magnetic moment is NOT associated with ____________.
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.
The unit Wbm-2 is equal to ______.
A beam of light travelling along X-axis is described by the electric field Ey = 900 sin ω(t - x/c). The ratio of electric force to magnetic force on a charge q moving along Y-axis with a speed of 3 × 107 ms-1 will be : [Given speed of light = 3 × 108 ms-1]
What is the relation between Tesla and Gauss?
A long straight wire AB carries a current of 5A. P is a proton travelling with a velocity of 2 × 106 m/s, parallel to the wire, 0.2 m from it and in a direction opposite to the current, as shown in Figure below. Calculate the force which magnetic field of the current carrying conductor AB exerts on the proton.
A circular coil of wire is made up of 200 turns, each of radius 10 cm. If a current of 0.5A passes through it, what will be the Magnetic field at the centre of the coil?
