OnlineCBT
Physics · UNITS AND MEASUREMENT
Practice questions & answers
Find a question, read its answer and explanation, then practise related questions.
Physics UNITS AND MEASUREMENT · Clear filters
131 questions
Physics · UNITS AND MEASUREMENT
The units for the fundamental or base quantities are called:
Read answer →Physics · UNITS AND MEASUREMENT
The dimensional formula of Stefan-Boltzmann constant \( \sigma \) in the equation \( E = \sigma T^4 A t \) (where \( E \) is energy, \( T \) is absolute temperature, \( A \) is area, and \( t \) is time) is:
Read answer →Physics · UNITS AND MEASUREMENT
In a system of units where Force \( (F) \), Velocity \( (v) \), and Time \( (t) \) are chosen as fundamental quantities, the dimensional formula of mass \( (m) \) is:
Read answer →Physics · UNITS AND MEASUREMENT
Which of the following supplementary units is defined as the ratio of the intercepted area of a spherical surface to the square of its radius?
Read answer →Physics · UNITS AND MEASUREMENT
Why is the ratio of molar volume to atomic volume of a gas at STP extremely large (of the order of \( 10^4 \) to \( 10^5 \))?
Read answer →Physics · UNITS AND MEASUREMENT
If the speed of light in vacuum is taken as the unit of speed and 1 year (\( 365.25\text{ days} \)) as the unit of time, the distance between the Sun and the Earth (which takes light \( 8\text{ minutes} \) and \( 20\text{ seconds} \) to travel) in this new unit of distance (light year) is:
Read answer →Physics · UNITS AND MEASUREMENT
In scientific notation, a number is expressed as \( a \times 10^b \). What is the range of values for \( a \)?
Read answer →Physics · UNITS AND MEASUREMENT
Which of the following physical quantities has the same dimensional formula as that of impulse?
Read answer →Physics · UNITS AND MEASUREMENT
What is the SI unit and symbol for plane angle?
Read answer →Physics · UNITS AND MEASUREMENT
How many significant figures are present in the length measurement written as \( 2.308 \text{ cm} \)?
Read answer →Physics · UNITS AND MEASUREMENT
Each side of a cube is measured to be \( 7.203\text{ m} \). What are the total surface area and the volume of the cube to appropriate significant figures?
Read answer →Physics · UNITS AND MEASUREMENT
Each side of a thin square sheet is measured to be \( 4.12\text{ m} \). The surface area of the square sheet, reported to the correct number of significant figures, is:
Read answer →Physics · UNITS AND MEASUREMENT
In a simple pendulum experiment, the percentage errors in the measurement of length \( L \) and time period \( T \) are \( 2\% \) and \( 1.5\% \) respectively. The maximum percentage error in the estimated value of acceleration due to gravity \( g \) is:
Read answer →Physics · UNITS AND MEASUREMENT
A student measures two different masses using a balance with a least count of \( 0.01 \text{ g} \). The measured masses are \( m_1 = 1.02 \text{ g} \) and \( m_2 = 9.89 \text{ g} \). The ratio of the relative error in the measurement of \( m_1 \) to that in \( m_2 \) is approximately:
Read answer →Physics · UNITS AND MEASUREMENT
What are the dimensions of the quantity \( [M L^2 T^{-2}] \) as derived in the dimensional analysis of physical equations?
Read answer →Physics · UNITS AND MEASUREMENT
If the relative density of lead is \( 11.3 \), what is its density in \( \text{kg m}^{-3} \)?
Read answer →Physics · UNITS AND MEASUREMENT
Which of the following supplementary units defined in SI is described as the ratio of the intercepted area \( dA \) of a spherical surface, described about the apex \( O \) as the centre, to the square of its radius \( r \)?
Read answer →Physics · UNITS AND MEASUREMENT
In the CGS system of units, the base units for length, mass and time are respectively:
Read answer →Physics · UNITS AND MEASUREMENT
A student measures the thickness of a wire using a screw gauge. The main scale reading is \( 0\text{ mm} \) and the circular scale reading is \( 52\text{ divisions} \). Given that the pitch of the screw gauge is \( 1\text{ mm} \) and it has \( 100\text{ divisions} \) on its circular scale, the measured diameter of the wire is:
Read answer →Physics · UNITS AND MEASUREMENT
The inner core of the Sun has a temperature exceeding \( 10^7\text{ K} \) and its outer surface has a temperature of about \( 6000\text{ K} \). Given the mass of the Sun \( = 2.0 \times 10^{30}\text{ kg} \) and radius of the Sun \( = 7.0 \times 10^8\text{ m} \), the mass density of the Sun is expected to be in the range of:
Read answer →Physics · UNITS AND MEASUREMENT
The size of a hydrogen atom is about \( 0.5 \text{ \AA} \). The total atomic volume of 1 mole of hydrogen atoms in \( \text{m}^3 \) is closest to: (Take \( \pi = 3.14 \), Avogadro's number \( N_A = 6.02 \times 10^{23}\text{ mol}^{-1} \))
Read answer →Physics · UNITS AND MEASUREMENT
The energy \( E \) of a damped oscillator is given by \( E = \frac{1}{2} m v^2 e^{-b t / m} + \frac{1}{2} k x^2 \), where \( m \) is mass, \( v \) is velocity, \( t \) is time, and \( x \) is displacement. For this equation to be dimensionally consistent, the dimensional formula of the damping constant \( b \) must be:
Read answer →Physics · UNITS AND MEASUREMENT
