Match the physical quantities with their correct SI units. List-I List-II (A) Planck's constant (I) kg m s - 2 (B) Torque (II) kg - 1 m 3 (C) Weight (III) m 2 kg s - 1 (D) Specific volume (IV) kg m 2 s - 2 The correct match is

A = III , B = IV , C = I , D = II

A = II , B = IV , C = I , D = III

A = IV , B = I , C = II , D = III

A = II , B = III , C = I , D = IV

Velocity v and acceleration a in two systems of units 1 and 2 are related as v 2 = n m 2 v 1 and a 2 = a 1 m n respectively. Here m and n are constants. The relations for distance and time in two systems respectively are

n 3 m 3 L 1 = L 2 and n 2 m T 1 = T 2

L 1 = n 4 m 2 L 2 and T 1 = n 2 m T 2

L 1 = n 2 m L 2 and T 1 = n 4 m 2 T 2

n 2 m L 1 = L 2 and n 4 m 2 T 1 = T 2

EASY

Earn 100

To calculate the effective length of pendulum, we measure :-

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Important Questions on Units and Measurements

MEDIUM

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

A huge circular arc of length $4.4 ly$ subtends an angle $4 s$ at the centre of the circle. How long it would take for a body to complete $4$ revolution if its speed is $8 AU$ per second?
Given : $1 ly = 9.46 \times 10^{15} m$

$1 AU = 1.5 \times 10^{11} m$

MEDIUM

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

The period of oscillation of a simple pendulum is

T = 2 π \sqrt{\frac{l}{g}} .

Measured value of

l

20.0 cm

, known to

1 mm

accuracy and time for

100

oscillations of the pendulum is found to be

90 s

using a wristwatch of

1 s

resolution. The accuracy in the determination of

g

EASY

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

If $E$ and $H$ represents the intensity of electric field and magnetizing field respectively, then the unit of $\frac{E}{H}$ will be:

EASY

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

A student measured the diameter of a small steel ball using a screw gauge of least count

0.001 cm .

The main scale reading is

5 mm

and zero division of the circular scale coincides with

25

divisions above the reference level. If the screw gauge has a zero error of

- 0.004 cm .

the correct diameter of the ball is__________

EASY

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

Match the physical quantities with their correct $SI$ units.

	List-I		List-II
(A)	Planck's constant	(I)	$kg m s^{- 2}$
(B)	Torque	(II)	${kg}^{- 1} m^{3}$
(C)	Weight	(III)	$m^{2} kg s^{- 1}$
(D)	Specific volume	(IV)	$kg m^{2} s^{- 2}$

The correct match is

EASY

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

Match the following?

Column -I		Column -II
(a)	Conductance	(i)	Gray
(b)	Magnetic Induction	(ii)	Lumen
(c)	Absorbed dose	(iii)	Tesla
(d)	Luminous flux	(iv)	Siemens

EASY

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

An accurate measurement implies that

EASY

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

Plane angle and solid angle have:

HARD

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

A person in front of a mountain is beating a drum at the rate of

40

per minute and hears no distinct echo. If the person moves

90 m

closer to the mountain, he has to beat the drum at

60

per minute to not hear any distinct echo. The speed of sound is

EASY

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

The nearest star to our solar system is

4.3

light years away. The distance of this star in Parsec is (Mean distance between the earth and the sun

= 1.5 \times 10^{11} m

and one light year

= 9.46 \times 10^{15} m)

EASY

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

The commutator bracket

[X Y, Z]

is expanded as

EASY

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

The angle of

1'

(minute of arc) in radian is nearly equal to

EASY

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

The distance of the Sun from earth is

1.5 \times 10^{11} m

and its angular diameter is

2000''

when observed from the earth. The diameter of the Sun will be

EASY

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

The angular speed of a fly-wheel making

180 rpm

is ________

MEDIUM

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

Velocity

(v)

and acceleration

(a)

in two systems of units

1

and

2

are related as

v_{2} = \frac{n}{m^{2}} v_{1}

and

a_{2} = \frac{a_{1}}{m n}

respectively. Here

m

and

n

are constants. The relations for distance and time in two systems respectively are

EASY

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

A physical quantity $P$ is described by the relation $P = a^{\frac{1}{2}} b^{2} c^{3} d^{- 4}$ . If the relative errors in the measurement of $a$ , $b$ , $c$ and $d$ respectively, are $2 %$ , $1 %$ , $3 %$ and $5 %$ . Then the relative error in $P$ will be:

EASY

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

A student measured the length of a rod and wrote it as 3.50 cm. Which instrument did he use to measure it ?

EASY

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

A spherometer has

20

threads per

cm

. Its circular scale has

100

divisions. The least count of the sphere is

EASY

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

The dimension of light year

MEDIUM

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

The angular diameter of a planet measured from earth is

90 " .

If the diameter of the planet is

π \times 10^{6} m,

then its distance from the earth is

To calculate the effective length of pendulum, we measure :-

Important Questions on Units and Measurements

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