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.

Pressure and humidity instrumentsElectrical measuring devicesMedical physics toolsNavigational instruments

Physics Measuring Instruments Questions

Multiple choice physics forces in fluids hydrometer and lactometer comparing density - relative density principle of floatation and its applications

The narrow stem in a hydrometer

  1. increases its sensitivity.

  2. increases upthrust on it

  3. raises its centre of gravity

  4. increases its size
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The narrow stem in a hydrometer increases its sensitivity.
The pressure increase with depth, so the lower part is made heavy to withstand high pressure.

Multiple choice physics forces in fluids hydrometer and lactometer comparing density - relative density principle of floatation and its applications

Give reasons as to why the lower end of a hydrometer is filled with mercury or lead.

  1. to lower its CG point

  2. to increase the height of its CG point

  3. to rotate in water

  4. to jump in water
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The lower end of a hydrometer is filled with mercury or lead in order to make it heavy so that it remains upright 

Multiple choice physics forces in fluids hydrometer and lactometer comparing density - relative density principle of floatation and its applications

Hydrometer is based on the principle of ___

  1. Principle of buoyancy

  2. Principle of floatation

  3. Pascals law

  4. Charle's law
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Hydrometer is based on the principle of floatation i.e., the weight of the liquid object displaced by the immersed portion of the hydrometer is equal to the weight of the hydrometer. 

Multiple choice physics forces in fluids hydrometer and lactometer comparing density - relative density principle of floatation and its applications

Match the following

1.Bulb filled with lead shots or mercury a. Increases sensitivity
2.The bulb helps the hydrometer to float b. Reduces center of gravity
3. Mercury c. Increases upthrust on the hydrometer
4. Narrow stem d. Gravity bulb

  1. 1-b, 2-d, 3-c, 4-a

  2. 1-b, 2-c, 3-a, 4-d

  3. 1-a, 2-d, 3-b, 4-c

  4. 1-d, 2-c, 3-b, 4-a
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Common hydrometer consists of three main parts the stem, the large bulb (floating bulb) and the small bulb filled with mercury or lead shots (gravity bulb). The floating bulb increases the upthrust on the hydrometer because when it submerges in the water completely it increases the weight of the water displaced. The smaller bulb is filled with lead shots or mercury which helps in lowering the center of gravity which enables the hydrometer to float vertically in the liquid. Thus the smaller bulb is called the gravity bulb. The narrow stem helps the hydrometer to sink effectively when dropped in a liquid with higher or lower relative density thus increasing the sensitivity of the hydrometer.

Multiple choice physics forces in fluids hydrometer and lactometer comparing density - relative density principle of floatation and its applications

Hydrometer is used to determine which of the following?

  1. Specific gravity of liquids.

  2. Boiling point of water.

  3. Specific heat of a matter.

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

Hydrometer is a devide used to determine the specific density of liquids.

A hydrometer is usually made of glass, and consists of a cylindrical stem and a bulb weighted with mercury to make it float upright. The liquid to test is poured into a tall container and the hydrometer is gently lowered into the liquid until it floats freely. The point at which the surface of the liquid touches the stem of the hydrometer correlates to specific gravity. Hydrometers usually contain a scale inside the stem, so that the person using it can read specific gravity. 

Multiple choice physics forces in fluids hydrometer and lactometer comparing density - relative density principle of floatation and its applications

Hydrometers usually contain a scale inside the stem, so that the person using it can read specific gravity.Is the statement True or False

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
A hydrometer is usually made of glass, and consists of a cylindrical stem and a bulb weighted with mercury to make it float upright. The liquid to test is poured into a tall container and the hydrometer is gently lowered into the liquid until it floats freely. The point at which the surface of the liquid touches the stem of the hydrometer correlates to specific gravity. Hydrometers usually contain a scale inside the stem, so that the person using it can read specific gravity. 
Multiple choice physics forces in fluids hydrometer and lactometer comparing density - relative density principle of floatation and its applications

Hydrometers are used to serve what purpose?

  1. For determining density of liquid

  2. Pressure measurement

  3. Viscosity measurement

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

Answer is A

A hydrometer is an instrument used to measure the specific gravity (relative density) of liquids; that is, the ratio of the density of the liquid to the density of water. A hydrometer is usually made of glass and consists of a cylindrical stem and a bulb weighted with mercury or lead shot to make it float upright

Multiple choice physics motion and measurement measuring length measurement of small and large distances measurement of distance

Parallax is the apparent displacement of an object because of:

  1. change in observer's point of view

  2. change in object's position

  3. changes both in observers point of view and object's position

  4. consistency in observer's point of view
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Astronomers use an effect called parallax to measure distances to nearby stars. Parallax is the apparent displacement of an object because of a change in the observer's point of view.

As the Earth orbits the sun, a nearby star will appear to move against the more distant background stars. Astronomers can measure a star's position once, and then again 6 months later and calculate the apparent change in position.