The pair(s) of physical quantities that do not have the same dimensions, is (are)
Reynolds number and coefficient of friction
Latent heat and gravitational potential
Curie and frequency of a light wave
Planck's constant and torque
If the constant of gravitation (G), Planck's constant (h) and the velocity of light (c) be chosen as fundamental units. The dimension of the radius of gyration is
h1/2c−3/2G1/2
h1/2c3/2G1/2
h1/2c−3/2G−1/2
h−1/2c−3/2G1/2
X = 3YZ2 find dimension of Y in (MKSA) system, if X and Z are the dimension of capacity and magnetic field respectively
M−3L−2T−4A−1
ML–2
M−3L−2T4A4
M−3L−2T8A4
In the relation P=αβe−αZkθ, P is pressure, Z is the distance, k is the Boltzmann constant and θ is the temperature. The dimensional formula of β will be:
[M0L2T0]
[M1L2T1]
[M1L0T−1]
[M0L2T−1]
The frequency of vibration of string is given by ν=p2lFm1/2. Here p is number of segments in the string and l is the length. The dimensional formula for m will be
[M0LT−1]
[ML0T−1]
[ML−1T0]
[M0L0T0]
Choose the correct match
(i) G, (ii) H, (iii) I, (iv) B, (v) C
(i) D, (ii) H, (iii) I, (iv) B, (v) G
(i) G, (ii) H, (iii) I, (iv) B, (v) G
None of the above
A wire has a mass of 0.3 ± 0.003 g, radius of 0.5 ± 0.005 mm and length of 0.6 ± 0.006 cm. The maximum percentage error in the measurement of its density will be
1
2
3
4
The base quantity among the following is
Speed
Weight
Length
Area
Assertion : ‘Light year’ and ‘Wavelength’ both measure distance.
Reason : Both have dimensions of time.
Assertion : Light year and year, both measure time.
Reason : Because light year is the time that light takes to reach the earth from the sun.
Assertion : Force cannot be added to pressure.
Reason : Because their dimensions are different.
Assertion : Linear mass density has the dimensions of [M1L-1To].
Reason : Because density is always mass per unit volume.
Assertion : Rate of flow of a liquid is defined as volume of liquid flowing per second.
Reason : The dimensions of rate of flow are M0L1T-1.
Assertion: Units of Rydberg constant R are m-1
Reason: It follows from Bohr’s formula v¯=R1n12−1n22, where the symbols have their usual meaning.
Assertion : Parallex method cannot be used for measuring distances of stars more than 100 light years away.
Reason : Because parallex angle reduces so much that it cannot be measured accurately.
Assertion : Number of significant figures in 0.005 is one and that in 0.500 is three.
Reason : This is because zeros are not significant.
Assertion: Out of three measurements l = 0.7 m; l = 0.70 m and l = 0.700 m, the last one is most accurate.
Reason: In every measurement, only the last significant digit is not accurately known.
Assertion: Mass, length and time are fundamental physical quantities.
Reason: They are independent of each other.
Assertion : Density is a derived physical quantity.
Reason : Density cannot be derived from the fundamental physical quantities.
Which of the following is not a unit of time?
Second
minute
hour
light year
Assertion: Nowadays a standard metre is defined in terms of the wavelength of light.
Reason: Light has no relation with length.
Assertion: Surface tension and surface energy have the same dimensions.
Reason: Because both have the same S.I. unit
Assertion : In y=Asin(ω t−kx), (ωt−kx) is dimensionless.
Reason : Because dimension of ω=[M0L0T].
Assertion : Radian is the unit of plane angle.
Reason : One radian is the angle subtended at the centre of a circle by an arc equal in length to the radius of the circle.
Choose any one of the following four responses :
Assertion : A.U. is much bigger than Å.
Reason : A.U. stands for astronomical unit and Å stands from Angstrom.
If both assertion and reason are true and the reason is the correct explanation of the assertion.
If both assertion and reason are true but reason is not the correct explanation of the assertion.
If assertion is true but reason is false.
If the assertion and reason both are false
Assertion: When we change the unit of measurement of a quantity, its numerical value changes.
Reason: Smaller the unit of measurement smaller is its numerical value.
If both assertion and reason are true but the reason is not the correct explanation of the assertion.
If the assertion is true but the reason is false.
If the assertion and reason both are false.
Assertion: Dimensional constants are the quantities whose values are constant.
Reason : Dimensional constants are dimensionless.
Assertion :The time period of a pendulum is given by the formula, T=2πl/g.
Reason : According to the principle of homogeneity of dimensions, only that formula is correct in which the dimensions of L.H.S. is equal to dimensions of R.H.S.
Assertion :In the relation f=12lTm, where symbols have standard meaning, m represent linear mass density.
Reason : The frequency has the dimensions of inverse of time.
Assertion: Avogadro number is the number of atoms in one gram mole.
Reason: Avogadro number is a dimensionless constant.
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