Deck 15: Physics Dimensions

Question 1

Tensile stress is equal to

A)Force per unit area
B)Force per unit volume
C)Extension per unit length
D)Extension per unit area

Answer 1

Force per unit area

Question 2

Dimensions of relative density are

A)mass × length-3
B)mass × length3
C)It has no dimensions, since it's a ratio of two densities
D)length 3 × mass^-1

Answer 2

It has no dimensions, since it's a ratio of two densities

Question 3

Dimensions of gravitational constant 'G' are: {{}}

A)[M]-1[L]3[T]-2
B)[M] [L]3[T]-2
C)[M]-1[L]2[T]-1
D)[M] [L]-1[T]2

Answer 3

[M]-1[L]3[T]-2

Question 4

A person of mass 'm' kg jumps from a height of 'h' meters, he will land on the ground with a velocity equal to:

A)√(2 × g × h
B)1/h × √(2 × g
C)2gh
D)2√(g × h

Question 5

In linear motion, the energy is given by 1⁄2mv 2. Similarly, in rotational motion, the rotational energy is given by {{}}

A)1/2 × I × ω; where I: moment of inertia of the body, ω: angular velocity
B)1/2 × I² × ω; where I: moment of inertia of the body, ω: angular velocity
C)1/2 × I × ω²; where I: moment of inertia of the body, ω: angular velocity
D)1/2 × I² × ω²; where I: moment of inertia of the body, ω: angular velocity

Question 6

Boyle's law states that

A)pressure of a gas is inversely proportional to its volume i.e. P × V = constant
B)pressure of a gas is directly proportional to its volume i.e. P⁄V = constant
C)pressure of a gas is inversely proportional to the square of its volume i.e. P × V² = constant
D)pressure of a gas is directly proportional to the square of its volume i.e. P ⁄ V² = constant

Question 7

Isothermal bulk modulus is equal to

A)Υ × P; where Υ: the ratio of the specific heat capacities of the gas, P: pressure
B)Pressure
C)The ratio of the specific heat capacities of the gas
D)Υ ⁄ P; where Υ: the ratio of the specific heat capacities of the gas, P: pressure

Question 8

Adiabatic bulk modulus is equal to:

A)Υ × P; where Υ: the ratio of the specific heat capacities of the gas, P: pressure
B)Pressure
C)The ratio of the specific heat capacities of the gas
D)Υ ⁄ P; where Υ: the ratio of the specific heat capacities of the gas, P: pressure

Question 9

Bernoulli's principle shows that, at points in a moving fluid where the potential energy change is very small

A)the pressure is low where the velocity is low and similarly, the pressure is high where the velocity is high
B)the pressure is low where the velocity is high and conversely, the pressure is high where the velocity is low
C)pressure becomes independent of the velocity of the moving fluid
D)pressure remain independent of the speed of the stationary fluid

Question 10

1 N (newton) is equal to {{}}

A)102 dynes
B)103 dynes
C)104 dynes
D)105 dynes

Question 11

Torricelli's theorem states that the velocity 'v' of the liquid emerging from the bottom of the wide tank is given by √(2gh). In practice, this velocity is:

A)equal to √(2gh
B)greater than √(2gh
C)lesser than √(2gh
D)independent of height and gravitational field strength

Question 12

Dimensions of Young's modulus are {{}}

A)[M]-1[L]-1[T]-2
B)[M]-1[L]-2[T]-2
C)[M] [L]-2[T]-2
D)[M] [L]-1[T]-2

Question 13

Kepler's 3rd law states that...

A)the periods of revolution of the planets are proportional to the cube of their mean distances from sun
B)the periods of revolution of the planets are inversely proportional to the cube of their mean distances from sun
C)the squares of the periods of revolution of the planets are proportional to the cube of their mean distance from sun
D)the squares of the periods of revolution of the planets are inversely proportional to the cube of their mean distance from sun

Question 14

Gradual decrease in x-ray beam intensity as it passes through material is called

A)attenuation
B)decay
C)radioactivity
D)imaging

Question 15

Attenuation coefficient of bone is 600 m^-1 for x-rays of energy 20 keV and intensity of beam of x-rays is 20 Wm^-2, then intensity of beam after passingthrough a bone of 4mm is {{}}

A)3 Wm^-2
B)2.5 Wm^-2
C)2.0 Wm^-2
D)1.8 Wm^-2

Question 16

For protons, the gyromagnetic ratio has the value {{}}

A)3 × 10⁸ rads^-1 T-1
B)2.68 × 10⁸ rads^-1 T-1
C)4 × 10⁸ rads^-1 T-1
D)5 × 10⁸ rads^-1 T-1

Question 17

Energy passing through unit area is

A)intensity of x-ray
B)frequency of x-ray
C)wavelength of x-ray
D)amplitude of x-ray

Question 18

speed of ultrasound depends upon

A)medium
B)amplitude
C)material
D)wavelength

Question 19

Bones look white in x-ray photograph because

A)they are bad absorbers of x-rays
B)they reflect x-rays
C)they are good absorbers of x-rays
D)they are bad absorbers of ultraviolet rays

Question 20

Larmor frequency depends upon the

A)individual nucleus
B)magnetic flux density
C)both A and B
D)energetic flux unit

Question 21

Acoustic impedance of human skin is {{}}

A)1.65 × 10⁶ kg m² s^-1
B)1.71 × 10⁶ kg m^-2 s^-1
C)2 × 10⁶kg m^-2 s^-1
D)2 × 10⁷ kg m^-3 s^-2

Question 22

In the best piezo-electric substances, the maximum value of strain is about

A)0.5 %
B)0.4 %
C)0.3 %
D)0.1 %

Question 23

With gel between skin and transducer percentage of reflected intensity of ultrasonic is

A)0.03%
B)0.05%
C)0.06%
D)0.08%

Question 24

Attenuation coefficient depends on

A)frequency of x-ray photons
B)wavelength of x-ray photons
C)energy of x-ray photons
D)amplitude of x-ray photons

Question 25

x-rays are filtered out of human body by using

A)cadmium absorbers
B)carbon absorbers
C)copper absorbers
D)aluminum absorbers