Tag: physics

Questions Related to physics

In a metre bridge experiment null point is obtained at $40$cm form one end of the wire when resistance X is balanced against another resistance Y. If X $<$ Y, then the new position of the null point from the same end, if one decides to balance a resistance of $3$X against Y, will be close to.

physics current electricity meter bridge meter bridge and problems on it galvanometer

  1. $80$ cm

  2. $75$ cm

  3. $67$ cm

  4. $50$ cm

Show answer
Correct Option: C
Explanation:

$\dfrac{x}{40}=\dfrac{y}{60}$
$\Rightarrow \dfrac{x}{y}=\dfrac{2}{3}$
$\therefore \dfrac{6k}{l}=\dfrac{3k}{100-l}$
$\Rightarrow l=67$.

In a Wheatstone's bridge, there resistances P, Q and R connected in the three arms and the fourth arm is formed by two resistances $S _1$ and $S _2$ connected in parallel. The condition for bridge to be balanced will be :

physics current electricity meter bridge meter bridge and problems on it galvanometer

  1. $\dfrac{P}{Q}=\dfrac{R}{S _1+S _2}$

  2. $\dfrac{P}{Q}=\dfrac{2R}{S _1+S _2}$

  3. $\dfrac{P}{Q}=\dfrac{R(S _1+S _2)}{S _1S _2}$

  4. $\dfrac{P}{Q}=\dfrac{R(S _1+S _2)}{2S _1S _2}$

Show answer
Correct Option: C
Explanation:

$\dfrac{P}{Q}=\dfrac{R}{S}$

$=\dfrac{R(S _1+S _2)}{S _1S _2}$. wher S is the equivalent resistance of $S _1 and S _2$

In a meter bridge an unknown resistance P is connected in the left gap and a $50 \Omega$ resistance in the right gap. Null point is obtained at x cm from the left end. The unknown resistance now shunted with an equal resistance. Find the value of the resistance in the right gap so that the null point is not shifted.

physics current electricity meter bridge meter bridge and problems on it galvanometer

  1. $60 \Omega$

  2. $38 \Omega$

  3. $25 \Omega$

  4. $50 \Omega$

Show answer
Correct Option: C

In a metre bridge experiment, the null point is obtained at $20\ cm$ from one end of the wire when the resistance $X$ is balanced against another resistance $Y$, where $Y>X$. What will be the new position of the null point, from the same end, if one decides to balance a resistance of $12/7$ against $Y$?

physics current electricity meter bridge meter bridge and problems on it galvanometer

  1. $30 cm$

  2. $40 cm$

  3. $50 cm$

  4. $60 cm$

Show answer
Correct Option: D

Two resistors $R _1$ and $R _2$ are connected in the left gap and right gap of a meter bridge, and the null point is obtained at $20\;cm$ from the left. On interchanging the resistors in the two gaps. the null point shift by.

physics current electricity meter bridge meter bridge and problems on it galvanometer

  1. $20\;cm$

  2. $40\;cm$

  3. $60\;cm$

  4. $80\;cm$

Show answer
Correct Option: C

In the measurement of resistance by a metre bridge, the known and unknown resistance are interchanged to eliminate 

physics current electricity meter bridge meter bridge and problems on it galvanometer

  1. end error

  2. index error

  3. random error

  4. error due to thermoelectric effect

Show answer
Correct Option: B

Two equal resistances are connected in the gaps of a meter bridge. If the resistance in the left gap is increased by $10\%$, the balancing point shift :

physics current electricity meter bridge meter bridge and problems on it galvanometer

  1. $10\%$ to right

  2. $10\%$ to left

  3. $9.6\%$ to right

  4. $4.8\%$ to right

Show answer
Correct Option: D
Explanation:
Let the Resistance be R,

Initially
$\dfrac{R}{R}  = \dfrac{l}{100-l}$
     $ \Rightarrow  l = 50 cm$
After 10% increase it is,

$ \Rightarrow  \dfrac{1.1R}{R} = \dfrac{l}{100-l}$

$ \Rightarrow  110  = 2.1 l$

$ \Rightarrow  l = \dfrac{110}{2.1} = 52.38$

$ \Rightarrow  \dfrac{\Delta l}{l} \times 100 = \dfrac{2.38}{50}\times 100  \approx 4.8$%

The balancing point in a meter bridge is 44 cm. If the resistances in the are  gaps are  inchanged   the new balance point is 

physics current electricity meter bridge meter bridge and problems on it galvanometer

  1. 44 cm

  2. 56 cm

  3. 50 cm

  4. 22 cm

Show answer
Correct Option: B
Explanation:

At balance position of meter bridge $=\dfrac{I}{{\left( {100 - I} \right)}}$ $=\frac{R}{S}$

Where $I$ is the balancing length$.$
So$,$ if value of $R$ and $S$ are inter changed the new $I$ limit will be $100-44=56$
Hence,
option $(B)$ is correct answer.

In a meter bridge setup, which of the following should be the properties of the one meter long wire?

physics current electricity meter bridge meter bridge and problems on it galvanometer

  1. High resistivity and low temperature coefficient

  2. Low resistivity and low temperature coefficient

  3. Low resistivity and high temperature coefficient

  4. High resistivity and high temperature coefficient

Show answer
Correct Option: A

A $6\Omega$ resistance is connected in the left gap of a meter bridge. In the second gap $3\Omega$ and $6\Omega$ are joined in parallel. The balance point of the bridge is at __

physics current electricity meter bridge meter bridge and problems on it galvanometer

  1. $75cm$

  2. $60cm$

  3. $30cm$

  4. $25cm$

Show answer
Correct Option: D