Tag: least count of vernier calliper and screw gauge

Questions Related to least count of vernier calliper and screw gauge

Unaware about the fact that analog ammeters and voltmeters can also have zero error, a student recorded following readings while determine resistance by Ohm's law 
If the ammeter has no zero error, the zero error is the voltmeter is 
 Obs, No. Voltage/V  Current/mA   Obs No.  Voltage/V  Current/mA
 1  1.0  40  4  7.0  160
 2  3.0  80  5  9.0  200
 3  5.0  120      
  1. $-1 V$

  2. $-1.5V$

  3. $0.5V$

  4. $1V$


Correct Option: A

A physical quantity $Q$ is released to four observable $x,y,z$ and $t$  by the relation
$Q=\dfrac {x^{2/5}z^{3}}{y\sqrt {t}}$ 
The percentage errors of measurement in $x,y,z$ and $t$ are $2.5\%,2\%,0.5\%$ and $1\%$ receptively. The percentage error in $Q$ will be

  1. $5\%$

  2. $4.5\%$

  3. $8\%$

  4. $7.75\%$


Correct Option: A

A steel tape is calibrated at $20 ^ { \circ } \mathrm { C }$. On a cold day when the temperature is $- 15 ^ { \circ } \mathrm { C }$ percentage error in the tape will be $\left[ \alpha _ { \text { steel } } = 1.2 \times 10 ^ { - 5 \cdot 0 } C ^ { - 1 } \right]$

  1. $0.035 \%$

  2. $0.042 \%$

  3. $0.012 \%$

  4. $0.018 \%$


Correct Option: B

The random error in the arithmetic mean of 100 observations is x, then random error in the arithmetic mean of 400 observation would be

  1. 4x

  2. $\dfrac { 1 }{ 4 } x$

  3. 2x

  4. $\dfrac { 1 }{ 2 } x$


Correct Option: B

A  faulty thermometer has its fixed point marked 5${ \circ  } _{ C }$ and 95${ \circ  } _{ C }$. this thermometer reads the temperature of a body as ${ 59 }^{ \circ  }$. The correct temperature on Celsius scale is  

  1. 59 ${ \circ } _{ C }$

  2. 8.6 ${ \circ } _{ C }$

  3. 65.56 ${ \circ } _{ C }$

  4. 58 ${ \circ } _{ C }$


Correct Option: C

If the error in measurement of momentum of a particle is $10$% and mass is known exactly,the permissible error in the determination of kinetic energy is

  1. $20$%

  2. $5$%

  3. $21$%

  4. $10$%


Correct Option: A

Length of a thin cylinder as measured by vernier callipers having least cound $0.01\ cm$ is $3.25\ cm$ and its radius of cross-section is measured by a screw gauge having least count $0.01\ mm$ as $2.75\ mm$. The percentage error in the measurement of volume of the cylinder will be

  1. $2\%$

  2. $3\%$

  3. $1\%$

  4. $1.5$


Correct Option: B

If the error in the measurement of radius of a sphere is 1%, then the error in the measurement of volume will be :

  1. 8%

  2. 5%

  3. 3%

  4. 1%


Correct Option: C
Explanation:

We know that a sphere has volume $V=\dfrac{4}{3}\pi r^3$ meaning $V \alpha r^{3}$.
Thus, error in measurement of volume will be $ 3 \times$ 1% = 3%.

The speed of a body is measured with a positive error of 30%. If the mass of the body is known exactly, the kinetic energy is calculated with an error of

  1. $60$%

  2. $30$%

  3. $69$%

  4. $39$%


Correct Option: A

While measuring the acceleration due to gravity by a simple pendulum, a student makes a positive error of 1% in the length of the pendulum and a negative error of 3% in the value of time period. His per-centre error in the n=measurement of g by the relation $g={ 4\pi  }^{ 2 }\left( I/T^{ 2 } \right) $ will be 

  1. 2%

  2. 4%

  3. 7%

  4. 10%


Correct Option: C