NEET Physics - New - Physical World and Measurement

Question - 1

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 of circular scale division coincides with 25 divisions above the reference level. If screw gauge has a zero error of - 0.004 cm, the correct diameter of the ball is:

• A 0.521 cm
• B 0.529 cm
• C 0.053 cm
• D 0.525 cm

Question - 2

A physical quantity of the dimensions of length  that can be formed out of c, G and  $\cfrac { { e }^{ 2 } }{ 4\pi { \varepsilon }_{ 0 } } \\$ is :  [c is velocity of light, G is universal constant of gravitation, e is charge]

• A ${ e }^{ 2 }{ \left[ { G }\frac { { e }^{ 2 } }{ 4\pi { \varepsilon }_{ 0 } } \right] }^{ { 1 }/{ 2 } }$
• B $\frac { 1 }{ { c }^{ 2 } } { \left[ \frac { { e }^{ 2 } }{ { G }4\pi { \varepsilon }_{ 0 } } \right] }^{ { 1 }/{ 2 } }$
• C $\frac { 1 }{ { c }^{ 2 } } { G }{ \frac { { e }^{ 2 } }{ 4\pi { \varepsilon }_{ 0 } } }$
• D $​​​​\frac { 1 }{ { c }^{ 2 } } { \left[ { G }\frac { { e }^{ 2 } }{ 4\pi { \varepsilon }_{ 0 } } \right] }^{ { 1 }/{ 2 } }$

Question - 3

Planck's constant (h), speed of light in vacuum (c) and Newton's gravitational constant (G) are three fundamental constants. Which of the following combinations of these has the dimension of length?

• A $\frac { \sqrt { hG } }{ { C }^{ { 3 }/{ 2 } } }$
• B $\frac { \sqrt { hG } }{ { C }^{ { 5 }/{ 2 } } }$
• C $\frac { \sqrt { hc } }{ { G}}$
• D $\frac { \sqrt { Gc } }{ { h }^{ { 3 }/{ 2 } } }$

Question - 4

If force (F), velocity (V) and time (T) are taken as fundamental units, then the dimensions of mass are:

• A $[F V^{-1} T^{-1}]$
• B $[FV^{-1}T]$
• C $[F V T^{-1}]$
• D $[FVT^{-2}]$

Question - 5

In an experiment four quantities a, b, c and dare measured with percentage error 1%, 2%, 3% and 4% respectively. Quantity P is calculated as follows:
$P = \frac {a^3b^2}{cd}$ Percentage error in P is :

• A 14%
• B 10%
• C 7%
• D 4%

Question - 6

The density of material in CGS system of unit is 4 g/$cm^3$. In a system of units in which unit of length is 10 cm and unit of mass is 100 g, the value of density of material will be :

• A 0.4
• B 40
• C 400
• D 0.04

Question - 7

The dimensions of Planck's constant are same as :

• A Energy
• B Power
• C Momentum
• D Angular momentum

Question - 8

The dimension of $\frac {1}{2} { \varepsilon }_{ 0 } E^2$ , where ${ \varepsilon }_{ 0 }$ is permittivity of free space and E is electric field, is :

• A $ML^{2}T^{-2}$
• B $ML^{-1}T^{-2}$
• C $ML^{2}T^{-1}$
• D $MLT^{-1}$

Question - 9

If the error in measurement of radius of sphere is 2% then the error in the determination of volume of the sphere will be :

• A 4%
• B 6%
• C 8%
• D 2%

Question - 10

Dimension of resistance in an electric circuit in terms of dimensions of mass M, of length L, of time T and of current I, would be :

• A $ML^{2}T^{-2}$
• B $ML^{2}T^{-1}I^{-1}$
• C $ML^{2}T^{-3}I^{-2}$
• D $ML^{2}T^{3}I^{-1}$