Current Electri...

In the arrangement shown in figure, the current through $$5 \Omega$$ resistor is

Electrical resistance of certain materials, known as superconductors, changes abruptly from a non zero value to zero as their temperature is lowered below a critical temperature $$T_C(0)$$. An interesting property of superconductors is that their critical temperature becomes smaller than $$T_C(0)$$ if they are placed in a magnetic field, i.e, the critical temperature $$T_c(B)$$ is a function of the magnetic field strength B. The dependence of $$T_C(B)$$ on B is shown in the figure.
In the graphs given, the resistance R of a superconductor is shown as a function of its temperature T for two different magnetic fields $$B_1$$(solid line) and $$B_2$$(dashed line). if $$B_2$$ is larger than $$B_1$$ which of the following graphs shows the correct variation of R with T in these fields?

A cell of emf $$E$$ and internal resistance $$r$$ is connected in series with an external resistance $$nr$$. Then, the ratio fo the terminal potential difference to E.M.F is

The emf of the cell $${E}_{2}$$ is:

The Kirchhoff's first law $$(\displaystyle\sum i=0)$$ and second law $$\left(\displaystyle \sum iR=\displaystyle\sum E\right)$$, where the symbols have their usual meanings, are respectively based on

  Which of the following relation is wrong?

The internal resistance of the cell $${E}_{2}$$ is:

If an alternate current main supply is given to be $$220 \ V$$. What would be the average electro motive force during a positive half cycle:

A potentiometer wire has length $$4$$m and resistance $$8\Omega$$.What should be the resistance that must be connected in series with the wire and an accumulator of emf $$2$$V, so as to get a potential gradient $$1$$mV per cm on the wire?

Two heater coils separately take $$10$$ minute and $$5$$ minute to boil certain amount of water. If both the coils are connected in series, the time taken will be