Meter Bridge

Q. For full scale deflection of total $50$ divisions, $50\text{mV}$ voltage is required in galvanometer. The resistance of galvanometer if its current sensitivity is $2\text{div/mA}$ will be :

1. $5\Omega$
2. $2\Omega$
3. $1\Omega$
4. $4\Omega$

Q. During an experiment with a meter bridge, the galvanometer shows a null point when the jockey is pressed at 40.0 cm using a standard resistance of $90\Omega$. The least count of the scale used in the meter bridge is 1mm. The unknown resistance is

1. \((60 \pm 0.15) \Omega\)
2. \((135 \pm 0.05) \Omega\)
3. \((60 \pm 0.25) \Omega\)
4. \((135 \pm 0.23) \Omega\)

Q. Is Wheatstone bridge balance equation valid if Capacitors are used in place of resistors ? ( C1/C2 =C3/C4)

Q. The given graph represents V - I characteristic for a semiconductor device. Which of the following statement is correct?

1. It is V - I characteristic for solar cell where point A represents open circuit voltage and point B represents short circuit current
2. It is for a LED and points A and B represent open circuit voltage and short circuit current respectively
3. It is for a solar cell and points A and B represent open circuit voltage and current, respectively
4. It is for a photodiode and points A and B represent open circuit voltage and current, respectively

Q. Potentiometer wire length is $10\text{m}$, having a total resistance of $10\Omega$. If a battery of emf $2\text{V}$ (of negligible internal resistance) and a rheostat are connected to it then the potential gradient is $2{\text{mV m}}^{-1}$. Find the resistance imparted through the rheostat:

1. $90\Omega$
2. $990\Omega$
3. $40\Omega$
4. $190\Omega$

Q. In fig., $AB$ is a potentiometer wire of length $10\text{m}$ and resistance $2\Omega$. With key $\left(K\right)$ open the balancing length is $5.5\text{m}$. However, on closing key $\left(K\right)$ the balancing length reduces to $5\text{m}$. The internal resistance of the cell $\left(E_1\right)$ is –

1. $1\Omega$
2. $0.01\Omega$
3. $0.1\Omega$
4. $0.2\Omega$

Q. The potential difference across the terminals of a battery is $8.4\text{V}$ when there is a current of $1.5\text{A}$ in the battery from the negative to the positive terminal. When the current is $3.5\text{A}$ in the reverse direction, the potential difference becomes $9.4\text{V}$.
$\left(a\right)$ What is the internal resistance of the battery?
$\left(b\right)$ What is the EMF of the battery ?

1. $0.2\Omega$, $5.2\text{V}$
2. $0.2\Omega$, $8.7\text{V}$
3. $0.4\Omega$, $5.2\text{V}$
4. $0.4\Omega$, $8.7\text{V}$

Q.

Why thick copper strips are used in metre bridge?

Q.

In a metre bridge experiment, two unknown resistances X and Y are connected to left and right gaps respectively and the balancing point is obtained at 20 cm from right. What will be the new position of the null point from left if one decides to balance a resistance of 4X against Y? (Assume that length of wire of metre bridge is 120 cm.)

1. 114 cm

2. 80 cm

3. 53.3 cm

4. 70 m

Q. In a metre bridge, the gaps are closed by resistances $P$ and $Q$, $P$ being less than $Q$. A balance is obtained when the jockey makes contact at a point of bridge wire $40\text{cm}$ from one end. On shunting the coil $Q$ with a resistance of $50\Omega$, the balance point is moved through $10\text{cm}$. The resistance $P$ and $Q$ are

1. $16.67\Omega ,25\Omega$
2. $25\Omega ,16.67\Omega$
3. $10\Omega ,25\Omega$
4. $8\Omega ,12\Omega$

Q.

Two equal resistances are connected in the gaps of a metre bridge. If the resistance in the left gap is increased by (10%) the balancing point shifts by

1. (9.6%) to right
2. (10%) to right
3. (10%) to left
4. (4.8%) to right

Q.

How can we convert a galvanometer into an ammeter of given range?

Q.

A 1000 w heating unit is designed to operate on a 120 V line the line volt drops to 110 V find the percentage drop in his eat output

16%

30%

9%

27%

Q. In a metre bridge experiment with resistance $R_1$ in the left gap and a resistance S in the right gap, balance point is obtained at 40 cm from zero end. With another resistance $R_2$ in left gap with same S in right gap, the balance point is obtained at 50 cm. If $R_1$ and $R_2$ are put in parallel in the left gap without changing S, the balancing length will be

1. 28.5 cm
2. 82.5 cm
3. 32.5 cm
4. 42.5 cm

Q. (a) Write the principle of working of a metre bridge.
(b) In a metre bridge, the balance point is found at a distance $l_1$ with resistance R and S as shown in the figure.

An unknown resistance X is now connected in parallel to the resistance S and the balance point is found at a distance $l_2$. Obtain a formula for X in terms of $l_1,l_2$ and S.

Q. Two unknown resistances $X$ and $Y$ are placed on the left and right gaps of a meter bridge. The null point in the galvanometer is obtained at a distance of $80\text{cm}$ from the left. A resistance of $100\Omega$ is now connected in parallel across $X$. The null point is then found by shifting the sliding contact left by $20\text{cm}$. Calculate $X$ and $Y$. [Neglect the end corrections]

1. 
   $$X=\frac{200}{50}\Omega ,Y=\frac{200}{50}\Omega$$
2. 
   $X=\frac{500}{30}\Omega$ , $Y=\frac{125}{3}\Omega$
3. 
   $X=\frac{100}{3}\Omega$ , $Y=\frac{25}{3}\Omega$
4. 
   $X=\frac{200}{3}\Omega$ , $Y=\frac{25}{3}\Omega$

Q. In a meter bridge, the gaps are closed by two resistances P and Q and the balance point is obtained at 40 cm.When Q is shunted by a resistance of $15\Omega$, the balance point shifts to 66.67 cm. The values of P and Q are

1. $20\Omega ,30\Omega$
   ​
2. $10\Omega ,15\Omega$
   ​
3. $5\Omega ,7.5\Omega$
   ​
4. $\frac{10}{3}\Omega ,5\Omega$
   ​

Q.

A galvanometer has a resistance of $3663\omega$. A shunt S is connected across it such that $\frac{1}{34}$ of the total current passes through the galvanometer. The value of the shunt is

Q. Potentiometer wire of length $10\text{m}$, having a total resistance of $10\Omega$. A battery of emf $2\text{V}$ of negligible internal resistance and a rheostat are connected to it. If the potential gradient is $20\text{mV/m}$, find the resistance of the rheostat.

1. $90\Omega$
2. $990\Omega$
3. $40\Omega$
4. $190\Omega$

Q.

The current in a coil of resistance $90\Omega$ is to be reduced by $90\%$. What value of resistance should be connected in parallel with it?

Q.

In a potentiometer of one metre length, an unknown emf voltage source is balanced at $60cm$ length of potentiometer wire, while a $3V$ battery is balanced at $45cm$ length. Then, the emf of the unknown voltage source is:

1. $3V$

2. $2.25V$

3. $4V$

4. $4.5V$

Q. 150.5uc and 20uc two points are placed at a distance of 2m from each other. Find a point on the joining line on which the electric field intensity is zero.

Q. 75. In the network shown in figure , C1 = 6micro F and C = 9 micro F . The equivalent capacitance between points P and Q is

Q. Two resistances X and Y are in the left and right gaps of a meter bridge. The balance point is 40 cm from left.Two resistances of $10\Omega$ each are connected in series with X and Y separately. The balance point is 45 cm. The value of X and Y are

1. $12\Omega ,16\Omega$
2. $12\Omega ,8\Omega$
3. $4\Omega ,6\Omega$
4. $8\Omega ,12\Omega$

Q.

A galvanometer of resistance 80 ohm, shunted by a resistance of 20 ohm is joined in series with a resistance of 200 ohm and cell of emf 1.5V What is the sensitivity of the galvanometer if it shows a deflection of 30 divisions.

Q.

Can you find very high resistance accurately with the help of a Metre bridge$?$

Q. A potentiometer wire $\text{AB}$ is $100\text{cm}$ long and has a total resistance of $10\Omega$. if the galvanometer shows zero deflection at the position $\text{C}$, then find the value of unknown resistance $\text{R}$.

1. $4\Omega$
2. $6\Omega$
3. $5\Omega$
4. $2.5\Omega$

Q. The heat generated in the coil of resistance 180 ohm which is connected to a silver voltmeter is 364.5 kj . If a steady current is passed through the circuit for15 min , find the mass of Ag that gets deposited on the cathode . Relative atomic mass of silver is 108 gm and faraday constant is 96500 c.

Q. A current of 30A is registered when terminal of cell of emf 1.5 volts are connected through an ammeter .The heat produced in 10s is

Q. 58.The meter bridge circuit shown in figure in balanced when jockey J divides wire AB into two parts AJ and BJ in the ratio 1:2. Then unknown resistance Q is:-