Current Electri...

The electromotive force resistance of a single cell equivalent to a combination of $$6$$ cells as shown in the figure will be:-

In a experiment for calibration of voltmeter a standard cell of e.m.f $$1.5 \ V$$ is balanced at $$300 \ cm$$ length of potentiometer wire. The potential difference across a resistance in the circuit is balanced at $$1.25 \ m$$. If a voltmeter is connected across the same resistance it reads $$0.65 \ V$$. The error in the volt meter is:

Two cells of electro motive force $$3 \ V$$ and $$5 \ V$$ and internal resistance $$r_1$$ and $$r_2$$ respectively are in series with an external resistance $$R$$. If the potential difference across 1st cell is zero, then $$R$$ is:- 

A coil of area $$500{cm}^{2}$$ having $$1000$$ turns is held perpendicular to a uniform magnetic field $$0.4G$$. The induced emf in the coil if it is turned through angle of $${180}^{o}$$ in $$\cfrac{1}{10}s$$ is

An AC supply is connected to a resistor. When the peak value of the $$e.m.f.$$ of the supply is $$V_0$$ and the frequency is $$f$$, the mean power disspated in the resistor is $$P$$. The supply frequency is then changed to $$2f$$, the peak value of the $$e.m.f.$$ remaining as $$V_0$$ what is now the mean power in the resistor?

The emf of a celll is $$E$$, and its internal resistance is $$1\ \Omega$$. A resistance of $$4\Omega$$ is joined to battery in parallel this is connected in secondary circuit of potentio meter the balancing length is $$160\ cm$$. If $$1V$$ cell balances for $$100\ cm$$ of potentio meter wire, the emf of cell $$E$$ is 

A conducting loop is placed in a uniform magnetic field of induction $$B$$ tesla with its plane normal to the field. Now, the radius of the loop starts shirking at the rate $$(\dfrac{dr}{dt})$$.
Then the induced emf at the instant when the radius is $$r$$ is

A thin uniform ring of radius R carrying uniformly distributed charge  Q and mass M rotates about its axis with angular velocity . The ratio of its magnetic moment and angular momentum is . 

In he circuit shown, the current in the $$1\Omega $$ resistor is :

The current i in the circuit (see figure) is :