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A voltmeter with resistance $500 Ω$ is used to measure the emf of a cell of internal resistance $4 Ω$ . The percentage error in the reading of the voltmeter will be

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Important Questions on Units and Measurements

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Physics>Mechanics>Units and Measurements>Errors in Measurement

The density of a material, in the shape of a cube, is determined by measuring three sides of the cube and its mass. If the relative errors in measuring the mass and length are

1.5 %

and

1 %

, respectively, the maximum error in determining the density is:

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Physics>Mechanics>Units and Measurements>Errors in Measurement

The length and width of a rectangular room are measured to be

(3 .95 \pm 0 .05) m

and

(3 .05 \pm 0 .05) m

, respectively, the area of the floor is

EASY

Physics>Mechanics>Units and Measurements>Errors in Measurement

An experiment is performed to obtain the value of acceleration due to gravity g by using a simple pendulum of length L. In this experiment time for 100 oscillations is measured by using a watch of 1 second least count and the value is 90.0 seconds. The length L is measured by using a meter scale of least count 1 mm and the value is 20.0 cm. The error in the determination of g would be :

EASY

Physics>Mechanics>Units and Measurements>Errors in Measurement

In an experiment, the percentage of error occurred in the measurement of physical quantities

A, B, C

and

D

are 1%, 2%, 3% and 4%, respectively. Then the maximum percentage of error in the measurement

X

, where

X = \frac{A^{2} B^{\frac{1}{2}}}{C^{\frac{1}{3}} D^{3}}

will be

MEDIUM

Physics>Mechanics>Units and Measurements>Errors in Measurement

If one takes into account the finite mass of the proton, the correction to the binding energy of the hydrogen atom is approximately (mass of proton

= 1 .60 \times 10^{- 27} kg,

mass of an electron

= 9 .10 \times 10^{- 31} kg

)

HARD

Physics>Mechanics>Units and Measurements>Errors in Measurement

A person measures the depth of a well by measuring the time interval between dropping a stone and receiving the sound of impact with the bottom of the well. The error in his measurement of time is

δ T = 0.01 s

and he measures the depth of the well to be

L = 20

meters. Take the acceleration due to gravity

g = 10 m s^{- 2}

and the velocity of sound is

300 m s^{- 1}

. Then the fractional error in the measurement,

\frac{δ L}{L}

is closest to

EASY

Physics>Mechanics>Units and Measurements>Errors in Measurement

A physical quantity $P$ is described by the relation $P = a^{\frac{1}{2}} b^{2} c^{3} d^{- 4}$ . If the relative errors in the measurement of $a$ , $b$ , $c$ and $d$ respectively, are $2 %$ , $1 %$ , $3 %$ and $5 %$ . Then the relative error in $P$ will be:

EASY

Physics>Mechanics>Units and Measurements>Errors in Measurement

Using screw gauge of pitch

0.1 cm

and

50

divisions on its circular scale, the thickness of an object is measured. It should correctly be recorded as,

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Physics>Mechanics>Units and Measurements>Errors in Measurement

In an experiment, the mass of an object is measured by applying a known force on it, and then measuring its acceleration. If in the experiment, the measured values of applied force and the measured acceleration are

F = (10.0 \pm 0.2) N

and

a = (1.00 \pm 0.01) m s^{- 2},

respectively, the mass of the object is

EASY

Physics>Mechanics>Units and Measurements>Errors in Measurement

The period of oscillation of a simple pendulum is given by

T = 2 π \sqrt{\frac{L}{g}}

, where

L

is the length of the pendulum and

g

is the acceleration due to gravity. The length is measured using a meter scale which has

500

divisions. If the measured value

L

50 cm

, the accuracy in the determination of

g

1.1 %

and the time taken for

100

oscillations is

100

seconds, what should be the possible error in measurement of the clock in one minute (in milliseconds)?

MEDIUM

Physics>Mechanics>Units and Measurements>Errors in Measurement

In a simple pendulum experiment for determination of acceleration due to gravity

(g)

, time taken for

20

oscillations is measures by using a watch of

1

second least count. The mean value of time taken comes out to be

30 s

. The length of the pendulum is measured by using a meter scale of least count

1 m m

and the value obtained is

55.0 c m

. The percentage error in the determination of

g

is close to

EASY

Physics>Mechanics>Units and Measurements>Errors in Measurement

In the density measurement of a cube, the mass and edge length are measured as

(10.00 \pm 0.10) k g

and

(0.10 \pm 0.01) m,

respectively. The error in the measurement of density is:

EASY

Physics>Mechanics>Units and Measurements>Errors in Measurement

A simple pendulum is being used to determine the value of gravitational acceleration

g

at a certain place. The length of the pendulum is

25.0 c m

and a stopwatch with

1 s

resolution measures the time taken for

40

oscillations to be

50 s

. The accuracy in

g

is:

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Physics>Mechanics>Units and Measurements>Errors in Measurement

A student measures the time period of

100

oscillations of a simple pendulum four times. The data set is

90 s

91 s

95 s

and

92 s

. If the minimum division in the measuring clock is

1 s

, then the reported mean time should be:

MEDIUM

Physics>Mechanics>Units and Measurements>Errors in Measurement

The power in an electrical circuit for a current of

5 \pm 0.4 A

and voltage

10 \pm 0.2 V

is measured at

10 %

error. To measure the power at

5 %

error the current should be measured at an error of

EASY

Physics>Mechanics>Units and Measurements>Errors in Measurement

A student measuring the diameter of a pencil of circular cross-section with the help of a vernier scale records the following four readings

5.50 mm

5.55 mm

5.34 mm

5.65 mm

. The average of these four reading is

5.5375 mm

and the standard deviation of the data is

0.07395 mm

. The average diameter of the pencil should therefore be recorded as :

EASY

Physics>Mechanics>Units and Measurements>Errors in Measurement

A physical quantity z depends on four observables

a, b, c

and

d

, as

z = \frac{a^{2} b^{\frac{2}{3}}}{\sqrt{c} d^{3}} .

The percentage of error in the measurement of

a, b, c

and

d

are

2 %, 1.5 %, 4 %

and

2.5 %

respectively. The percentage of error in

z

is :

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Physics>Mechanics>Units and Measurements>Errors in Measurement

Two students $P$ and $Q$ perform an experiment to verify Ohm's law for a conductor with resistance $R$ . They use a current source and a voltmeter with the least counts of $0.1 mA$ and $0.1 mV$ , respectively. The plots of the variation of voltage drop $V$ across $R$ with current $I$ for both are shown below.

Question Image

The statement which is most likely to be correct?

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Physics>Mechanics>Units and Measurements>Errors in Measurement

The percentage errors in quantities

P

Q

R

and

S

are

0.5 %

1 %

3 %

and

1.5 %

respectively in the measurement of a physical quantity

A= \frac{P^{3} Q^{2}}{\sqrt{R} S}

. The maximum percentage error in the value of

A

will be:

HARD

Physics>Mechanics>Units and Measurements>Errors in Measurement

The current voltage relation of diode is given by I = (e¹⁰⁰⁰^V/T - 1) mA, where the applied voltage V is in volts and the temperature T is in degree Kelvin. If a student makes an error measuring

\pm 0.01 V

while measuring the current of 5 mA at 300 K, what will be the error in the value of current in mA ?

A voltmeter with resistance 500 Ω is used to measure the emf of a cell of internal resistance 4 Ω. The percentage error in the reading of the voltmeter will be

Important Questions on Units and Measurements

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A voltmeter with resistance $500 Ω$ is used to measure the emf of a cell of internal resistance $4 Ω$ . The percentage error in the reading of the voltmeter will be