NEET Physics units and measurements Test-8

NEET Physics units and measurements Test-8

1. If M is the magnetic moment# B is the magnetic induction and T is the time# then MBT2 has the dimensions


2. A quantity X is given by [math] { varepsilon }_{ 0 }Lfrac { riangle V }{ riangle t } [/math] where ε 0 is the permittivity of free space# L. is a length delta V is a potential difference and delta t is a time interval. The dimensional formula for X is the same as that of


3. Pressure depends on distance as# [math] P=frac { alpha }{ eta } exp(-frac { alpha z }{ k heta } ) [/math]where α# β are constants# z is distance# ‘k’ is Boltzmann’s constant and ‘ θ ‘ is temperature. The dimension of β are


4. In the equation [math] frac { 1 }{ Peta } =frac { y }{ { k }_{ Beta }T } [/math] when P is the pressure# y is the distance# kb is Boltzmann constant and T is the temperature# dimensions of beta are


5. Assertion (A) Energy is a derived quantity
Reason (R) Energy is a scalar


6. Assertion (A) Though Fermi is a unit of distance# it is not a fundamental unit
Reason (R) All practical units need not be fundamental units


7. Assertion (A) In mechanics# we treat length# mass and time as the three basic or fundamental quantities.
Reason (R) Length# mass and time cannot be obtained from one another.


8. Assertion (A) Light year is a unit of time.
Reason (R) Light year is the distance travelled by light in vacuum in one year.


9. Assertion (A) The magnitude of a physical quantity does not change when the system of units is changed from S.I system to C.G.S system.
Reason (R)The magnitude of a physical quantity is independent of system of units


10. Assertion (A)When we change the unit of measurement of a quantity# its numerical value changes
Reason (R)Smaller the unit of measurement smaller is its numerical value.


11. Assertion (A)Electric current is a scalar
Reason (R) All fundamental physical quantities are scalars.


12. Assertion (A)If u1 and u2 are units and n1 n2 are their numerical values in two different systems then n1 > n2 & u1< u2.
Reason (R) The numerical value of physical quantity is inversely proportional to unit


13. Assertion (A) The equation y = x + t cannot be true where x# y are distances and t is time
Reason (R) Quantities with different dimensions cannot be added


14. Assertion (A) Plane angle is a dimensionless quantity
Reason (R)All unit less quantities are dimensionless


15. Assertion (A) Dimensions of constant of proportio-nalities can be derived from dimensional method
Reason (R)Numerical value of constant of proportion-ality can be found from experiments only.


16. Assertion (A) Angular momentum and Plank’s constant are dimensionally similar but they are not identical physical quantities
Reason (R)Dimensionally similar quantities need not be identical


17. Assertion (A) A dimensionally correct equation may not be a correct equation of usage

Reason (R) Every expression which is dimensionally correct need not be numerically correct


18. Assertion (A) The Dimensional formula of a physical quantity is same in any system of units.
Reason (R)Dimensional formula is independent of system of units.


19. Assertion (A) Solid angle is a dimensionless quantity and it is a supplementary quantity
Reason (R) All supplementary quantities are dimensionless


20. Assertion (A) The dimensional formula for relative velocity is same as that of the change in velocity
Reason (R) Relative velocity of P w.r.t. Q is the ratio of velocity of P and that of Q


21. Assertion (A) Energy cannot be divided by volume.
Reason (R) Dimensions of energy and volume are different.



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