Physics · General Awareness

Physics Measuring Instruments

1,180 Questions

Physics measuring instruments are essential tools used to measure various physical quantities. This topic covers devices like hygrometers, oscilloscopes, and sphygmomanometers. It is a highly scoring section in general science and general awareness examinations.

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Physics Measuring Instruments Questions

Multiple choice physics measurements and experimentation vernier calliper and screw gauge least count of vernier calliper and screw gauge measurement of length

In an experiment, mass of an object is measured by applying a known force on it, and then measuring its acceleration. If, in the experiment, the measured values of applied force and the measured acceleration are $F=10.0\pm 0.2N$ and $a=1.00\pm 0.01m/{s}^{2}$, respectively, the mass of the object is

  1. $10.0Kg$
  2. $10.0\pm 0.1Kg$
  3. $10.0\pm 0.3Kg$
  4. $10.0\pm 0.4Kg$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$F=Ma$
$M=\cfrac { f }{ a } $
$\cfrac { \Delta M\times 100 }{ M } =\cfrac { \Delta f }{ f } \times 100+\cfrac { \Delta a }{ a } \times 100$
$=\cfrac { 0.2 }{ 10 } +\cfrac { 0.01 }{ 1 } $
$\Delta M=0.03\times 10$
$\therefore$ $10.0\pm 0.3Kg$

Multiple choice physics fluids pressure in fluids pressure in liquids introduction to pressure

A barometer which measures atmospheric pressure more accurately is ..........

  1. Fortin's barometer

  2. mercury barometer

  3. anaeroid barometer

  4. Torricelli barometer
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A barometer which measures atmospheric pressure most accurately is mercury barometer.

Hence, option B is correct.

Multiple choice botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

Passage of ascent of sap is shown by

  1. Osmometer

  2. Porometer

  3. Manometer

  4. Blockage experiment
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Dixon and jolly demonstrated the process of translocation of  water and minerals from base to apex of the plant and is known as the ascent of sap as proposed by Dixon and Jolly. The complex tissue xylem in plants is responsible for translocation water and minerals in plants. In blockage experiment, two small shoots of a woody plant are taken. Their cut ends are so prepared that in one shoot phloem is blocked with wax, while in the other xylem is blocked. Now the cut ends are submerged in water. After some time, the shoot with its xylem blocked shows wilting, but the shoot with its phloem blocked remains unaffected.

Multiple choice physics properties of material substances poisson ratio poisson's ratio elastic energy

A cube of wood supporting $200 gm$ mass just in water $(\rho =1g/cc)$. When the mass is removed, the cube rises by $2cm$. The volume of cube is

  1. $1000 cc$
  2. $800cc$
  3. $500 cc$

  4. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Let the edge of cube be $L$ when mass is on the cube of wood 
$200g+{ L }^{ 3 }{ d } _{ wood }g={ L }^{ 3 }{ d } _{ water }g$
$\Rightarrow { L }^{ 3 }{ d } _{ wood }g={ L }^{ 3 }{ d } _{ water }g$
$\Rightarrow { L }^{ 3 }{ d } _{ wood }g={ L }^{ 3 }{ d } _{ water }g-200g$
$\Rightarrow { L }^{ 3 }{ d } _{ wood }={ L }^{ 3 }d-200$
When mass is removed
${ L }^{ 3 }{ d } _{ wood }-\left( L-2 \right) { L }^{ 2 }{ d } _{ water }\quad \longrightarrow \left( 2 \right) $
From $(1)$ and $(2)$
${ L }^{ 3 }{ d } _{ water }-200=\left( L-2 \right) { L }^{ 2 }{ d } _{ water }$
But ${ d } _{ water }=1$
$\therefore$    ${ L }^{ 3 }-200={ L }^{ 2 }\left( L-2 \right) $
$\therefore$    $L=10cm$.
Multiple choice physics units and measurement: error analysis significant figures significant figures and rounding of digits units and measurements

Relative density of a metal may be found with the help of spring balance. In air the spring balance reads $(5.00\pm 0.05)$ N and in water it reads $(4.00\pm 0.05)$N. Relative density would be:

  1. $(5.00\pm 0.05)N$
  2. $(5.00\pm$ 11%)
  3. $(5.00\pm 0.10)$
  4. $(5.00\pm$ 6%)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Relative density $=\dfrac {\text {Weight of body in air}}{\text {Loss of weight in water}}$$=\dfrac {5.00}{5.00-4.00}=\dfrac {5.00}{1.00}$

$\dfrac {\Delta \rho}{\rho}\times 100=\left (\dfrac {0.05}{5.00}+\dfrac {0.05}{1.00}\right )\times 100$
                    $=(0.01+0.05)\times 100$
                    $=0.06\times 100$
                    $ =6$% 
$\therefore$ Relative density $=5.00\pm$ 6%

Multiple choice physics units and measurement: error analysis significant figures significant figures and rounding of digits units and measurements

Find density when a mass of 9.23 kg occupies a volume of $\displaystyle 1.1m^{3}$ with due regard to significant figures.

  1. $\displaystyle 8.4 kg/m^{3}$
  2. $\displaystyle 8.39 kg/m^{3}$
  3. $\displaystyle 8.3 kg/m^{3}$

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Mass $= 9.23\ kg$ .... 3 significant figures

Volume $= 1.1\  m^3$ .... 2 significant figures

Therefore, $density = mass/volume = 8.4\ kg/m^3$ 

Multiple choice physics units and measurement: error analysis significant figures significant figures and rounding of digits units and measurements

The mass of a beaker is found to be ($10.1 \pm 0.1)gm $ when empty and $(17.3 \pm 0.1)gm$ when partially filled with a liquid. What is the best value for the mass of the liquid together with the possible limits of accuracy?

  1. $(7.2 \pm 0.2)gm$
  2. $(7.2 \pm 0.1)gm$
  3. $(7.1 \pm 0.2)gm$
  4. $(7.2 \pm 0.3)gm$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Here mass of the liquid , $m=m _2-m _1=17.3-10.1=7.2 gm$

So the relative error, $\dfrac{\Delta m}{m}=\pm\left[\dfrac{\Delta m _1}{m _1}+\dfrac{\Delta m _2}{m _2}\right]$
or $\Delta m=\pm\left[\dfrac{\Delta m _1}{m _1}+\dfrac{\Delta m _2}{m _2}\right]\times m=\pm[0.1/10.1+0.1/17.3]\times 7.2=\pm 0.1 gm$
Thus mass of liquid with possible accuracy $=(7.2\pm 0.1) gm$

Multiple choice bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

OP of a solution can be measured by 

  1. Photometer

  2. Osmometer

  3. Calorimeter

  4. Plasmolysis
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

An osmometer is a device for measuring the osmotic strength of a solution.
Photometer is an instrument for measuring the intensity of light.

A calorimeter is an object used in the process of measuring the heat capacity. 
Plasmolysis is the contraction of the protoplast of a plant cell as a result of loss of water from the cell.
Thus, the correct answer is option (B). 

Multiple choice bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

OP of a cell can be measured by 

  1. Manometer

  2. Photometer

  3. Calorimeter

  4. Plasmolysis
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Manometer is a device that is used to measure pressure. Photometer is a device that is used to the intensity of light. Calorimeter is a device that is used to measure the amount of heat involved in a reaction. Osmotic pressure is the pressure that must be applied in order to prevent the passage of solvent due to osmosis. The OP of a cell can be measured by plasmolysis. The OP of a cell is equal to the OP of a solution that results in the incipient plasmolysis in the cell.

Thus, the correct answer is option D.

Multiple choice physics effects of electric current electric generator ac generator magnetic effects of electric current

A device for producing electric current is ________.

  1. Ammeter

  2. Voltmeter

  3. Generator

  4. Galvanometer
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Generator is the device used for the production of electric current.

It works on the principle of Faraday's laws of Electromagnetic induction in which due to the change in the magnetic flux linked with the coil there is potential induced in the coil and since the circuit is closed the current flows throw the circuit.
Generator can be AC or DC type. It is an active device and acts as the source for current.

Multiple choice physics electromagnetic waves properties and uses of different radiation electromagnetic spectrum spectrum

Microwaves are detected by

  1. barometer

  2. point contact diodes

  3. thermopiles

  4. the eye
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Point contact diodes, commonly called crystals, are the oldest microwave semiconductor devices. Unlike the pn-junction diode, the point-contact diode depends on the pressure of contact between a point and a semiconductor crystal for its operation.One section of the diode consists of a small rectangular crystal of n-type silicon. A fine beryllium-copper, bronze-phosphor, or tungsten wire presses against the crystal and forms the other part of the diode During the manufacture of the point contact diode, a relatively large current is passed from the the wire to the silicon crystal. The result of this large current is the formation of a small region of p-type material around the crystal in the vicinity of the point contact. Thus, a pn-junction is formed which behaves in the same way as a normal pn-junction. The pointed wire is used instead of a flat metal plate to produce a high-intensity electric field at the point contact without using a large external source voltage.

Multiple choice

Which chemical engineering principle is concerned with the design and operation of equipment for the measurement and control of process variables?

  1. Instrumentation

  2. Control Systems

  3. Sensors

  4. Actuators
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Instrumentation involves the design and operation of equipment used to measure and control process variables such as temperature, pressure, flow rate, and composition.

Multiple choice

What is the primary function of a barometer?

  1. To measure wind speed

  2. To measure air temperature

  3. To measure atmospheric pressure

  4. To measure humidity
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A barometer is a device used to measure atmospheric pressure.