Anyone pls send some extra ques for physics chapter units and measurement class 11th....
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Answers
The number of significant figures in 0.06900 is
(a) 5
(b) 4
(c) 2
(d) 3
The sum of the numbers 436.32, 227.2 and 0.301 in appropriate significant figures is
(a) 663.821
(b) 664
(c) 663.8
(d) 663.82
The mass and volume of a body are 4.237 g and 2.5 cm3, respectively. The density of the material of the body in correct significant figures is
(a) 1.6048 g cm-3
(b) 1.69 g cm-3
(c) 1.7 g cm-3
(d) 1.695 g cm-3
The numbers 2.745 and 2.735 on rounding off to 3 significant figures will give
(a) 2.75 and 2.74
(b) 2.74 and 2.73
(c) 2.75 and 2.73
(d) 2.74 and 2.74
The length and breadth of a rectangular sheet are 16.2 cm and 10.1cm, respectively. The area of the sheet in appropriate significant figures and error is
(a) 164 ± 3 cm2
(b) 163.62 ± 2.6 cm2
(c) 163.6 ± 2.6 cm2
(d) 163.62 ± 3 cm2
Which of the following pairs of physical quantities does not have same dimensional formula?
(a) Work and torque.
(b) Angular momentum and Planck’s constant.
(c) Tension and surface tension.
(d) Impulse and linear momentum.
Measure of two quantities along with the precision of respective measuring instrument is A = 2.5 m s-1 ± 0.5 ms-1 B = 0.10 s ± 0.01 s
The value of A B will be
(a) (0.25 ± 0.08) m
(b) (0.25 ± 0.5) m
(c) (0.25 ± 0.05) m
(d) (0.25 ± 0.135) m
You measure two quantities as A = 1.0 m ± 0.2 m, B = 2.0 m ± 0.2 m. We should report correct value for √AB as:
(a) 1.4 m ± 0.4 m
(b) 1.41m ± 0.15 m
(c) 1.4m ± 0.3 m
(d) 1.4m ± 0.2 m
Which of the following measurements is most precise?
(a) 5.00 mm
(b) 5.00 cm
(c) 5.00 m
(d) 5.00 km.
The mean length of an object is 5 cm. Which of the following measurements is most accurate?
(a) 4.9 cm
(b) 4.805 cm
(c) 5.25 cm
(d) 5.4 cm
Young’s modulus of steel is 1.9 × 1011 N/m2. When expr essed in CGS units of dynes/cm2, it will be equal to (1N = 105 dyne, 1m2 = 104 cm2)
(a) 1.9 × 1010
(b) 1.9 × 1011
(c) 1.9 × 1012
(d) 1.9 × 1013
If momentum (P ), area (A) and time ( T ) are taken to be fundamental quantities, then energy has the dimensional formula
(a) (P1 A-1 T1)
(b) (P2 A1 T1)
(c) (P2 A-1/2 T1) (
d) (P1 A1/2 T-1)
Multiple Choice Questions (MCQ II)
On the basis of dimensions, decide which of the following relations for the displacement of a particle undergoing simple harmonic motion is not correct:
Units and Measurements
If P, Q, R are physical quantities, having different dimensions, which of the following combinations can never be a meaningful quantity?
(a) (P – Q)/R
(b) PQ – R
c) PQ/R
(d) (PR – Q2)/R
(e) (R + Q)/P
Photon is quantum of radiation with energy E = hν where ν is frequency and h is Planck’s constant. The dimensions of h are the same as that of
(a) Linear impulse
(b) Angular impulse
(c) Linear momentum
(d) Angular momentum
If Planck’s constant (h ) and speed of light in vacuum (c ) are taken as two fundamental quantities, which one of the following can, in addition, be taken to express length, mass and time in terms of the three chosen fundamental quantities?
(a) Mass of electron (me)
(b) Universal gravitational constant (G)
(c) Charge of electron (e)
(d) Mass of proton (mp)
Which of the following ratios express pressure?
(a) Force/ Area
(b) Energy/ Volume
(c) Energy/ Area
(d) For ce/ Volume
Which of the following are not a unit of time?
(a) Second
(b) Parsec
(c) Year
(d) Light year
Very Short Answer Type Questions
Why do we have different units for the same physical quantity?
The radius of atom is of the order of 1 Å and radius of nucleus is of the order of fermi. How many magnitudes higher is the volume of atom as compared to the volume of nucleus?
Name the device used for measuring the mass of atoms and molecules.
Express unified atomic mass unit in kg.
A function f (θ) is defined as:
Units and Measurements
Why is it necessary for q to be a dimensionless quantity?
Why length, mass and time are chosen as base quantities in mechanics?
Short Answer Type Questions
(a) The earth-moon distance is about 60 earth radius. What will be the diameter of the earth (approximately in degrees) as seen from the moon?
(b) Moon is seen to be of (½)°diameter from the earth. What must be the relative size compared to the earth?
(c) From parallax measurement, the sun is found to be at a distance of about 400 times the earth-moon distance. Estimate the ratio of sun-earth diameters.
Which of the following time measuring devices is most precise?
(a) A wall clock.
(b) A stop watch.
(c) A digital watch.
(d) An atomic clock.
all are questions