Question
A rectangular wire loop of width a is suspended from the insulated pan of a spring balance, as shown in A current i exists in the anti-clockwise direction in the loop. A magnetic field Bexists in the lower region. Find the change in the tension of the spring if the current in the loop is reversed.

Answer


Current anticlockwise

Since the horizontal Forces have no effect.

Let us check the forces for current along AD & BC [Since there is no $\overrightarrow{\text{B}}$ ]

In AD, F = 0

For BC

F = iaB upward

Current clockwise

Similarly, F = - iaB downwards

Hence change in force = change in tension

= iaB - (-iaB) = 2 iaB

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

At what distance should two charges, each equal to 1C, be placed so that the force between them equals your weight?
Explain internal reflection and total internal reflection and also derive the necessary formula for it.
Explain the construction of compound microscope with the help of figure and derive the equation of magnification.
Write the expression for the magnetic force acting on a charged particle moving with velocity n in the presence of magnetic field B.

A neutron, an electron and an alpha particle moving with equal velocities, enter a uniform magnetic field going into the plane of the paper as shown. Trace their paths in the field and justify your answer.

A capacitor of capacitance $100\mu\text{F}$ is connected to a battery of 20 volts for a long time and then disconnected from it. It is now connected across a long solenoid having 4000 turns per metre. It is found that the potential difference across the capacitor drops to 90% of its maximum value in 2.0 seconds. Estimate the average magnetic field produced at the centre of the solenofd during this period.
Consider the situation of the previous problem. Suppose the production of the radioactive isotope starts at t = 0. Find the number of active nuclei at time t.
A partially plane polarised beam of light is passed through a Polaroid. Show graphically the variation of the transmitted light intensity with angle of rotation of the Polaroid.
Figure, shows an aluminium rod joined to a copper rod. Each of the rods has a length of 20cm and area of cross section 0.20cm2. The junction is maintained at a constant temperature 40°C and the two ends are maintained at 80°C. Calculate the amount of heat taken out from the cold junction in one minute after the steady state is reached. The conductivities are KAI = 200wm-1°C-1 and Kcu = 400wm-1°C-1.

Two blocks of equal mass m are tied to each other through a light string. One of the blocks is pulled along the line joining them with a constant force F. Find the tension in the string joining the blocks.
Let AE denote the energy gap between the valence band and the conduction band. The population of conduction electrons (and of the holes) is roughly proportional to $\text{e}^{\frac{-\Delta\text{E}}{2\text{kT}}}.$ Find the ratio of the concentration of condu.ction electrons in diamond to that in silicon at room temperature 300K. $\Delta\text{E}$ for silicon is 1.1eV and for diamond is 6.0eV. How many conduction electrons are likely to be in one cubic metre of diamond?