Tag: measurements and experimentation

Questions Related to measurements and experimentation

The length of a second pendulum at the surface of earth is $1\ m$. The length of second pendulum at the surface of moon, where $g$ is $\dfrac{1}{6} th$ that of earth's surface.

physics measurements and experimentation a few applications of linear shm simple pendulum example of simple harmonic motion

  1. $\dfrac{1}{6} m$

  2. $6 m$

  3. $\dfrac{1}{36}m$

  4. $36 m$

Show answer
Correct Option: A
Explanation:

We know that the time period of a second pendulum is $2s$ .

At earth ,
                $T=2\pi \sqrt{l _{e}/g _{e}}$
                $2=2\pi\sqrt{l _{e}/g _{e}}$
or             $g _{e}=\pi^{2}l _{e}$  ...............................eq1

At moon ,
                $T=2\pi \sqrt{l _{m}/g _{m}}$
or             $2=2\pi \sqrt{l _{m}/(g _{e}/6)}$  , given   $g _{m}=g _{e}/6$
or             $2=2\pi\sqrt{6l _{m}/\pi^{2}l _{e}}$   ,   putting the value of $g _{m}$ from  eq1
or             $l _{m}=l _{e}/6$
Now , given  $l _{e}=1m$

Hence ,     $l _{m}=1/6m$

The length of the simple pendulum which ticks seconds is:

physics measurements and experimentation a few applications of linear shm simple pendulum example of simple harmonic motion

  1. $0.5$m

  2. $1$m

  3. $1.5$m

  4. $2$m

Show answer
Correct Option: B
Explanation:

The time period of a simple pendulum is
$T = 2 \pi \sqrt{\dfrac{L}{g}}$
where L is the length of the pendulum.
or $ L = \dfrac{gT^2}{4 \pi^2}$
The time period of the simple pendulum which ticks seconds is $2$s.
$\therefore T = 2s$
Substituting in (i), we get


$L = \dfrac{(9.8 m s^{-2})(2s)^2}{4 \times (3.14)^2} = 1m$

A second's pendulum is mounted in a rocket. Its period of oscillation will decrease when the rocket is:

physics measurements and experimentation a few applications of linear shm simple pendulum example of simple harmonic motion

  1. moving up with uniform velocity

  2. moving up with uniform acceleration

  3. moving down with uniform acceleration

  4. moving around the earth in a geostationary orbit

Show answer
Correct Option: B
Explanation:

Correct answer= B

As the rocket accelerates upwards, pseudo force acts in the opposite direction of propagation.
=> Pseudo force acts in downward direction and gets added up to gravitational force.
=> Effective gravity= gravitational force+ pseudo force
                                >Gravitational force
=>             g'        >         g       where g' = effective gravity
Since time period of oscillation of pendulum= √(L/g)
       where L= length of the pendulum
                   g= gravitational force acting on the pendulum
=> In this situation,
          time period of oscillation of pendulum=√(L/g')
Since g' > g
=>     √(L/g')      <     √(L/g)
=>  Time period of oscillation decreases

Complete the following:
$1$ quintal $=$ _________ kg
physics measurements and experimentation measuring distance of celestial bodies unconventional units of measurements units of mass

  1. $10$

  2. $100$

  3. $1000$

  4. $0.01$

Show answer
Correct Option: B
Explanation:

A quintal is a unit of mass in the metric system which is equal to $100$ kilograms.

Which of the following is smallest unit of distance ?

physics measurements and experimentation measuring distance of celestial bodies unconventional units of measurements units of mass

  1. Milimeter

  2. Angstrom

  3. Fermi

  4. Meter

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Correct Option: C
Explanation:

Out of these, meter is the largest.
$1 millimeter = 10^{-3} m$
$1 Angstrom = 10^{-10}m$
$1 Fermi = 10^{-15}m$
Thus Fermi is the smallest.

Parsec in the unit of which physical quantity?

physics measurements and experimentation measuring distance of celestial bodies unconventional units of measurements units of mass

  1. Time

  2. Distance

  3. Frequency

  4. Angular acceleration

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Correct Option: B
Explanation:

Parallactic second or parsec is a unit of distance defined as the distance at which one astronomical unit subtends an angle of one arcsecond, which is equal to 3.26 light years.

State whether the following statement is True or False. 

The prefix used for $\displaystyle { 10 }^{ 9 }$ is nano.

physics measurements and experimentation measuring distance of celestial bodies unconventional units of measurements units of mass

  1. True

  2. False

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Correct Option: B
Explanation:

The prefix used for $\displaystyle { 10 }^{ -9 }$ is nano and prefix used for $10^9$ is Giga

In CGS system, gram is the unit of mass. State true or false.

physics measurements and experimentation measuring distance of celestial bodies unconventional units of measurements units of mass

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

Gram is the unit of mass in the CGS system

State whether the following statement is True or False. 

One micron is equal to $\displaystyle { 10 }^{ -3 }m$.

physics measurements and experimentation measuring distance of celestial bodies unconventional units of measurements units of mass

  1. True

  2. False

Show answer
Correct Option: B
Explanation:
We know that  $1 \mu m = 10^{-6} \ m$
Thus the given statement is false.

Which of the following is different from others?

physics measurements and experimentation measuring distance of celestial bodies unconventional units of measurements units of mass

  1. Micron

  2. Light year

  3. Mole

  4. Angstrom

Show answer
Correct Option: C
Explanation:

Micron, light year and Angstrom are the units of distance whereas mole is the measure of amount of substance in a matter. So, mole is different from others.