Units & Dimensions Test

Result

Units & Dimensions Test - 8

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

The accuracy in the measurement of time for 20 oscillations of pendulum for the following measurements, t₁ = 39.6 s, t₂ = 39.9 s and t₃ = 39.5 s is:

A
± 0.005 s

B
± 0.3 s

C
± 0.5 s

D
± 0.4 s

Solution

According to the problem time for 20 oscillations of a pendulum
t₁= 3 9.6s, t₂= 39.9s, t₃ =3 9.5s
It is quite obvious from these observations that the least count by the water is 0.1s. As measurements have only one decimal place.
► Precision in measurement = least count of measuring instrument = 0.1s
► Precision in 20 oscillations = 0.1
Therefore, Precision in 1 oscillation = 0.1/ 20= 0.005.
Question 2
1 / -0

Which of the following is caused by careless handling?

A
Systematic error

B
Gross error

C
Random error

D
None of the mentioned

Solution

Gross errors are mostly due to lack of knowledge, judgment and care on the part of experiment. That is Gross error is caused by careless handling.
Question 3
1 / -0

A student measures the distance covered and time taken by a body under free fall which was initially at rest. He uses this data for estimating g, the acceleration due to gravity. If the maximum percentage error in measurement of the distance and the time are e₁ and e₂respectively, then the maximum possible percentage error in the estimation of g is:

A
e₂- e₁

B
e₁+ 2e₂

C
e₁+ e₂

D
e₁- 2e₂

Solution

From the releation

h= 1/2gt² ⇒ g = 2h/t²
Taking natural logarithms on both sides, we get
ln (g) = ln (h) - 2ln (t) + ln (2)
Differentiating
for maximum permissible errors , we add both the errors . so
Question 4
1 / -0

Error in the measurement of radius of a sphere is 1%. The error in the calculated value of its volume is:

A
1%

B
3%

C
5%

D
7%

Solution

∵ V = (4/3)πr³
% error is volume = 3 × error in radius = 3 × 1 = 3%
Question 5
1 / -0

The error in two readings of A are 0.01 and -0.03, then mean absolute error is?

A
0.002

B
-0.004

C
0.02

D
-0.02

Solution

Absolute error
Mean absolute error
Question 6
1 / -0

At a certain place, the acceleration due to gravity is determined using a simple pendulum. The length of the pendulum is 25.0 cm and a stopwatch with least count is 1 s measures the time taken by the pendulum for 40 oscilations to be 50 s. the accuracy in the measurement of g is:

A
4.40 %

B
3.40 %

C
2.40 %

D
5.40 %

Solution
Question 7
1 / -0

The most suitable instrument for measuring the size of an atom is:

A
Electron microscope

B
Vernier calliper

C
Optical Microscope

D
Screw gauge

Solution

Only electron microscope has resolution of 0.5-0.6 Angstrom which is less than the size of an atom.
Question 8
1 / -0

Which is the most accurate atomic clock?

A
Carbon-12 clock

B
Carbon atom clock

C
Caesium atom clock

D
Stop clock

Solution

Cesium 133 is the element most commonly chosen for atomic clocks.
Question 9
1 / -0

The method used to measure the distance of a planet from the earth is:

A
Parallax method

B
Archimedes’ method

C
Newton’s method

D
Galileo’s method

Solution

The astronomers mainly use parallax method to find distances to objects like other planets. To calculate the distance to a star or to a planet, astronomers observe it from different places along Earth's orbit around the Sun.
Question 10
1 / -0

What is the percentage error in the physical quantity A if it is related to four other physical quantities a, b, c and d as The percentage error in measurement of a, b, c and d are 1%, 3%, 2% and 2% respectively.

A
12%

B
10%

C
14%

D
11%

Solution