NEET Physics Current Electricity MCQs

In a potentiometer experiment, the balancing length for a cell is found to be $l$. If the driver cell is replaced by another cell of double the emf, what will be the new balancing length, assuming all other parameters remain constant?

A potentiometer is being used to compare two cells of emfs $E_1$ and $E_2$. The balancing lengths are found to be $l_1$ and $l_2$ respectively. If a resistance R is connected across $E_2$, its balancing length changes to $l_3$. Which of the following relations must hold true?

A galvanometer with a resistance of $50 \Omega$ and a full-scale deflection current of $100 \mu A$ is to be converted into a voltmeter with a range of 0-5V. A resistance $R_x$ is connected in series with the galvanometer. Simultaneously, an identical galvanometer is converted into an ammeter of range 0-10mA by connecting a shunt resistance $R_s$ in parallel. What is the relationship between $R_x$ and $R_s$?

Two cells of emf $E_1$ and $E_2$ and internal resistances $r_1$ and $r_2$ respectively are connected in parallel. The equivalent emf and internal resistance of the combination will be:

A potentiometer wire of length 100cm has a resistance of 10Ω. It is connected in series with a resistance R and a cell of emf 2V and negligible internal resistance. A source of emf 10mV is balanced against a length of 40cm of the potentiometer wire. What is the value of the resistance R?

A cell of emf E and internal resistance r is connected across a variable external resistance R. The graph of terminal potential difference V against current I reaches a maximum value of V. What is the relationship between E, r, and this maximum value of V?

n identical cells, each of emf E and internal resistance r, are connected in series to form a closed circuit. If one cell is reversed, what is the current in the circuit?

A battery of emf 10V and internal resistance 3Ω is connected to a resistor. If the current in the circuit is 0.5A, what is the terminal voltage of the battery when the circuit is closed?

A metre bridge setup uses a standard resistance of $10\Omega$. A resistance wire of unknown value and uniform cross-section is connected across the left gap. The null point is obtained at $60\,cm$ from the left end. If the radius of the unknown wire is doubled without changing its length or resistivity, the new null point will be at:

In a metre bridge experiment, the null point is found at $40\,cm$ from the left end. A $12\Omega$ resistor is connected in parallel with the unknown resistance and the null point shifts to $60\,cm$. What is the value of the unknown resistance?