Revision on unit one

n an experiment using a light microscope, the length of the smallest visible object is 0.2092 μm. Which of the following represents this value expressed in metres

• 20.092×10^-7 m

• 2.092×10^-7 m

• 2.092×10^-3 m

• 292×10^-7m

Which of the following mathematical operations has a physical meaning if the physical quantities A and B have different dimensional formula?

• A (A - B)

• A/B

• 3A+2B

• A - 2B

from the opposite figure

• 𝐶 = 𝐵

• B = - C

• 𝐷 = 2 𝐶

• A = D

If the relative error in measuring the mass of a box is 1.6%, and the absolute error is 0.4 kg, then the actual mass of the box = ........................

• 4 kg

• 25 kg

• 400 kg

• 0.25kg

The ratio between the displacement of an object rotating in a circular path to its distance in one complete revolution:

• Zero

• 𝛑 /2

• 1/ 𝛑

• 𝛑

The two physical quantities 𝑋 and 𝑌 have the same dimension formula 𝑀𝐿^-1𝑇^-2. So the dimension formula for 5𝑋+2y is

• 𝑀𝐿^-1𝑇^-2

• 𝑀𝐿^-2𝑇⁴

• 𝑀⁰𝐿𝑇^-2

• has no physical meaning

The scalar (dot) product is equal to the half of vector (cross) product when Ɵ =………………..

• 26.56

• 45

• 63.43

• 56.26

The scalar (dot) product is equal to the vector (cross) product when Ɵ =………………..

• 26.56

• 45

• 63.43

• 56.26

Two vectors 𝐀⃗⃗ and 𝐁⃗⃗ have values 8 units and 6 units respectively and the angle between them is 𝟑𝟎°.So the result of cross(vector) product of the two vectors is ……………unit

• 12

• 24

• 41.6

• 10

A rectangle whose length is ( 𝟒 ±𝟎.𝟏 ) 𝐂𝐦 and its width is ( 𝟏𝟎 ±𝟎.𝟐 )𝐂𝐦,then

The absolute error in of its area =  ………….. cm

• 0.3

• 1.8

• 2

• 2.5