Q31. Taking into account the significant figures, what is the value of $(9.99~\text{m}-0.0099~\text{m})$ ?
$9.98~\text{m}$
$9.980~\text{m}$
$9.9~\text{m}$
$9.9801~\text{m}$
Explanation:
Hint: Recall the rules of the significant figures.
Step: Find the significant figures in the given quantity.
The correct value with proper significant figure =
Hence, option (1) is the correct answer.
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#185446
Exam: NEET – 2020
Q32.
A screw gauge has the least count of $0.01~\text{mm}$ and there are $50$ divisions in its circular scale. The pitch of the screw gauge is:
$0.25~\text{mm}$
$0.5~\text{mm}$
$1.0~\text{mm}$
$0.01~\text{mm}$
Explanation:
Hint: Least count = pitch/(number of the divisions)
Step: Find the pitch of the screw gauge.
The least count of the screw gauge is given by;
Least count = pitch/(number of the divisions)
Hence, option (2) is the correct answer.
#185422
Exam: NEET – 2020
Q33. If $E$ and $G$ respectively, denote energy and gravitational constant, then $\dfrac{E}{G}$ has the dimensions of:
$[ML^0T^0]$
$[M^2L^{-2}T^{-1}]$
$[M^2L^{-1}T^{0}]$
$[ML^{-1}T^{-1}]$
Explanation:
Hint:
Step 1: Find the dimensions of and .
The dimensions of energy
The dimensions of is given by;
Step 2: Find the dimensions of
Hence, option (3) is the correct answer.
We see that your answer is incorrect, Please mention reason from these.
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#277136
Exam: NEET – 2021
Q34.
A screw gauge gives the following readings when used to measure the diameter of a wire:
Main scale reading: $0$ mm
Circular scale reading: $52$ divisions
Given that $1$ mm on the main scale corresponds to $100$ divisions on the circular scale, the diameter of the wire that can be inferred from the given data is:
$0.26$ cm
$0.052$ cm
$0.52$ cm
$0.026$ cm
Explanation:
Hint: The diameter of the wire is given by the sum of the main scale reading and the circular scale reading.
Step 1: Find the least count of the screw gauge.
Step 2: Find the diameter of the wire.
Diameter of the wire = Reading of the screw gauge = M.S.R + C.S.R
The diameter of the wire is given by;
Hence, option (2) is the correct answer.
#277111
Exam: NEET – 2021
Q35.
If force $[F]$ , acceleration $[A]$ and time $[T]$ are chosen as the fundamental physical quantities, then find the dimensions of energy:
$\left[FAT^{-1}\right]$
$\left[FA^{-1}T\right]$
$\left[FAT\right]$
$\left[FAT^{2}\right]$
Explanation:
Hint: The dimensions of energy is .
Step: Find the dimensions of energy in terms of force, acceleration, and time.
The energy can be written as;
Hence, option (4) is the correct answer.
#277105
Exam: NEET – 2021
Q36. The percentage error in the measurement of $g$ is:
(Given, $g=\frac{4\pi^2L}{T^2},L=(10\pm0.1)~\text{cm, }T=(100\pm1)~\text s$ )
$2\%$
$5\%$
$3\%$
$7\%$
Explanation:
Hint: Use the concept of relative error.
Step: Find the percentage error in the measurement of .
The expression of the is given by;
Hence, option (3) is the correct answer.
#346633
Exam: NEET – 2022
Q37. The physical quantity that has the same dimensional formula as pressure is:
Force
Momentum
Young’s modulus of elasticity
Coefficient of viscosity
Explanation:
Hint: The dimensions of Stress and pressure are the same.
Step 1: Find the dimensions of Young’s modulus of elasticity.
Young’s modulus of elasticity is defined as the ratio of stress and strain. Strain is a dimensionless quantity. Therefore, the dimensions of Young’s modulus of elasticity are the same as the dimensions of stress.
Step 2: Find the dimensional formulae of stress.
Stress = Force/ Area.
Pressure = Force / Area
We can see that stress, pressure, and Young’s modulus of elasticity have the same dimensions.
Hence, option (3) is the correct answer.
#346595
Exam: NEET – 2022
Q38.
The determination of the value of acceleration due to gravity $(g)$ by simple pendulum method employs the formula, $g=4\pi^2\dfrac{L}{T^2}$
The expression for the relative error in the value of $g$ is:
Step: Find the expression for the relative error in .
The expression of acceleration due to gravity by simple pendulum method is given by;
The relative error in is given by;
Hence, option (1) is the correct answer.
#339775
Exam: NEET – 2022
Q39.
When the circular scale of a screw gauge completes $2$ rotations, it covers $1$ mm over the pitch scale. The total number of circular scale divisions is $50.$ The least count of the screw gauge in metres is:
$10^{-4}$
$10^{-5}$
$10^{-2}$
$10^{-3}$
Explanation:
Hint:
Step 1:
Find the pitch of the screw gauge.
The pitch of the screw gauge is given by;
Step 2: Find the least count of the screw gauge.
Hence, option (2) is the correct answer.
#339753
Exam: NEET – 2022
Q40. The area of a rectangular field (in $\text{m}^2$ ) of length $55.3$ m and breadth $25$ m after rounding off the value, for correct significant digits is:
$14\times10^{2}$
$138\times10^{1}$
$1382$
$1382.5$
Explanation:
Hint: Apply the rules of significant figures.
Step 1: Find the area of the field.
The area of the field
Step 2: Find the result with appropriate significant figures.
The result should have as many significant figures as in the measurement given with the least significant figure.
Area = =
Hence, option (1) is the correct answer.
