Physics Class - Measurement and Units Quiz

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Questions and Answers

Which of the following is an example of a derived quantity?

Charge

Length

Speed (correct)

Mass

What is the unit of current in the S.I. System?

A (correct)

What is the formula for calculating pressure?

Force/Volume

Mass/Time

Energy/Distance

Force/Area (correct)

Which of the following quantities is NOT considered a fundamental quantity?

Acceleration Signup and view all the answers

Which quantity is calculated using the formula distance/time?

Speed Signup and view all the answers

What is meant by high precision in measurements?

A measurement with small random error Signup and view all the answers

Which condition defines high accuracy in measurements?

Small random error and small systematic error Signup and view all the answers

How is absolute error typically determined if the least count is known?

It is taken as equal to the least count Signup and view all the answers

What does relative error indicate?

The absolute error divided by the size of the measurement Signup and view all the answers

If a measurement has a high least count, what can be inferred?

It may have significant error Signup and view all the answers

Which of the following correctly describes the least count?

The difference between one main scale division and one Vernier scale division Signup and view all the answers

Which of the following statements is true regarding systematic errors?

They tend to remain constant in repeated measurements Signup and view all the answers

What happens to measurements with high random errors?

They can lead to unreliable results Signup and view all the answers

What does the term 'second' refer to in the context provided?

Duration of periods in cesium-133 atom Signup and view all the answers

What physical setup allows the measurement of an ampere?

Two infinite conductors in vacuum Signup and view all the answers

How much force is produced per meter of length between the conductors when maintaining an ampere?

2 x 10^-7 Newton Signup and view all the answers

Which of the following best describes the transition between hyperfine levels in the cesium-133 atom?

It is a change in energy levels within the atom. Signup and view all the answers

What is the significance of the cesium-133 atom in defining time?

It defines the frequency of a specific radiation. Signup and view all the answers

What condition must be met for the measurement involving two conductors?

They need negligible circular cross-section. Signup and view all the answers

Why is the cesium-133 atom chosen for accurate timekeeping?

It has a consistent radiation period. Signup and view all the answers

What does maintaining an ampere in the specified conductor arrangement achieve?

It establishes a measurable force between the conductors. Signup and view all the answers

What happens when a screw gauge has a positive zero error?

It shows an excess reading even when jaws are in contact. Signup and view all the answers

How is the least count of a screw gauge calculated?

Pitch divided by total number of divisions on circular scale. Signup and view all the answers

In the context of screw gauges, what does a negative zero error imply?

There is less reading than the actual measurement. Signup and view all the answers

What is the role of the angular scale on the thimble of a screw gauge?

To allow precise angular adjustments during measurement. Signup and view all the answers

What would be the least count of a screw gauge if each turn of the head moves the spindle by 1 mm and there are 100 divisions on the angular scale?

0.01 mm Signup and view all the answers

What defines a zero error in a screw gauge?

The reading when no object is present, but there is an excess due to material on the jaws. Signup and view all the answers

Which formula represents the calculation for negative zero error?

<ul> <li>[Total number of vsd – vsd coinciding] × L.C.</li> </ul> Signup and view all the answers

What is the implications of having an excess material on the jaws of a screw gauge?

It results in a positive zero error. Signup and view all the answers

What is the effect of a single fixed pulley on the direction of force?

It changes the direction of force. Signup and view all the answers

In the case of mass m2, what is the equation that represents the forces acting on it?

m2g - T = m2a Signup and view all the answers

What does the term 'inertial frames of reference' refer to?

A reference frame at rest or in uniform motion. Signup and view all the answers

What does the tension T equal for mass m1 in the pulley system?

T = m1 a Signup and view all the answers

What is the acceleration of the system when considering the masses m1 and m2 together?

a = (m2 g) / (m1 + m2) Signup and view all the answers

What is the relationship between the forces acting on mass m2 in the pulley system?

m2g - T = m2a Signup and view all the answers

How does the mass of a pulley affect the acceleration of the connected masses in the system?

A massless pulley does not affect acceleration. Signup and view all the answers

What is the formula that gives the tension in terms of the forces acting on mass m2?

T = m2(g - a) Signup and view all the answers

What characterizes static friction?

There is no relative motion between objects. Signup and view all the answers

Which expression represents the relationship involving kinetic friction?

$F_k = m g ext{sin} q$ Signup and view all the answers

When determining the forces in a system with connected bodies, what must be true about their motion?

Their displacements, velocities, and accelerations should be the same along the constraint. Signup and view all the answers

What is the primary condition for kinetic friction to occur?

Objects must be in motion relative to each other. Signup and view all the answers

Which of the following factors typically affects the magnitude of static friction?

The texture of the surfaces in contact. Signup and view all the answers

What is the relationship between the force of static friction and the applied force?

Static friction is equal to the applied force until the maximum is reached. Signup and view all the answers

Which of the following correctly describes kinetic friction?

It acts to oppose the relative motion between surfaces. Signup and view all the answers

In a system of connected bodies subject to motion, what is the impact of a normal constraint?

It requires the same displacements along the constraint. Signup and view all the answers

Study Notes

Units, Dimensions, Measurements and Practical Physics

Fundamental quantities do not depend on other quantities for definition. Examples include length, mass, time and electric current
Derived quantities are expressed in terms of fundamental quantities. Examples include speed, volume, and acceleration
SI units are the standard units of measurement in the International System of Units. Examples include kilogram (kg) for mass, meter (m) for length, and second (s) for time
Supplementary units are derived units used for specific physical quantities. Examples include radian (rad) for plane angle and steradian (sr) for solid angle
Dimensional formula shows physical quantities in terms of fundamental quantities. Example, Force = ML T-2
Dimensional analysis can check the dimensional correctness of a physical relation and derive relationships between quantities
SI prefixes are used to express very large or small quantities in multiples of 10. Examples include kilo (k) for 10³, mega (M) for 10⁶

Basic Mathematics used in Physics

Roots of a quadratic equation ax² + bx + c = 0 are given by x = (-b ± √(b² - 4ac))/2a
Sum of the roots of a quadratic equation = -b/a
Product of the roots of a quadratic equation = c/a
Logarithm: log₁₀(mn) = log₁₀(m) + log₁₀(n)
Arithmetic progression (AP) a, a+d, a+2d, ... , sum of n terms Sₙ = n(2a + (n-1)d)/2
Geometric progression (GP) a, ar, ar², ... , nth term = arⁿ⁻¹, sum of n terms Sₙ = a(1-rⁿ)/(1-r).

Trigonometry

Trigonometric functions (sine, cosine, tangent, etc.) relate angles and sides of triangles.
Trigonometric identities (sin² θ + cos² θ = 1, etc.) are used for calculations.
Trigonometric functions can be computed from 0° to 90°, 0 radians to π/2 radians, and further calculated from these principle values for wider angles.

Differentiation

Differentiation gives the rate of change of a function. Example, if y = x², then dy/dx = 2x
Maxima and minima of a function y=f(x) can be found using the first and second derivatives (dy/dx = 0 and d²y/dx² < 0 for maximum; and dy/dx = 0 and d²y/dx² > 0 for minimum)
Differentiation is necessary for calculating velocity and acceleration from position functions in kinematics.
Integration is necessary for calculating displacement and distance from velocity functions, and velocity from acceleration.

Formulae for determination of area and volume

Area of a square (side)²
Area of a rectangle (length × breadth)
Area of a triangle (½ × base × height)
Area of a circle πr² (r = radius)
Volume of a cube (side)³
Volume of a cuboid (length × breadth × height)
Volume of a sphere (4/3)πr³ (r = radius)

Vectors

A vector quantity possesses both magnitude and direction. For example, displacement, velocity, and force. This should always be represented by an arrow.
Vector addition using triangle law, if two vectors are represented by two sides of a triangle in the same order, the third side opposite to the third angle will give the resultant vector.
Vector addition using parallelogram law, if two vectors are represented by two adjacent sides of a parallelogram, the diagonal passing through their common point will represent the resultant.
In a closed path, or polygon or vector sum to zero, that means all the vectors are making zero resultant
Components of a 3-D vector
Scalars and Vectors

Work, Energy and Power

Work is the product of force and displacement in the direction of force. W = Fd cos θ, where θ is the angle between force and displacement.
Power is the rate of doing work. P = W/t
Kinetic energy KE = ½mv²
Potential energy, if the potential energy is conservative force, then it will be equal in magnitude but opposite in sign to work done, if the given position is considered as reference position. For example, if a mass is released from a height, then the potential energy will decrease to become zero as the height of the mass from the earth's surface is zero.
Conservative forces, work done is independent of path e.g. gravitational force, electrostatic forces.
Non-conservative forces, work done dependent on path e.g. friction, viscous force

Collisions and Centre of Mass

Centre of mass is a point where the entire mass of a system is concentrated,
Linear momentum is conserved in collisions if no external forces are present.
Types of collisions: Elastic, Inelastic, Perfectly inelastic.

Rotational Motion

Moment of inertia of a rigid body is a measure of its resistance to rotational motion
Different bodies: Moment of inertia formula for different shapes like ring, disc, sphere
Parallel axis theorem: Moment of inertia about any axis is equal to the moment of inertia about a parallel axis through the center of mass plus the product of the mass and the square of the distance between the two axes.

Thermodynamics

Zeroth law of thermodynamics states that if two systems are in thermal equilibrium with a third system they are in thermal equilibrium with each other.
First law of thermodynamics states that the heat supplied to a system is equal to the sum of the change in internal energy and work done by the system.
Different kinds of thermodynamics processes: isothermal, adiabatic, isochoric (constant volume) , isobaric (constant pressure)

Electrostatics

Electric charge is a fundamental property of matter. The SI unit is Coulomb (C)
Coulomb's law gives the force between two point charges q₁ and q₂: F = kq₁q₂/r²
Electric field is force per unit charge. E = F/q
Potential difference gives the work done per unit charge to move a charge between 2 points
Due to electric charges and their distribution, some basic formulas of electric fields and potentials are required for problems or questions.

Current Electricity

Electric current is the rate of flow of charge. I = ΔQ/Δt
Ohm's law states that the current through a conductor is proportional to the potential difference across it. V = IR
Resistance (R), conductivity (σ), resistivity (ρ) are important concepts related to current flow in circuits
Different combinations of different electrical resistances: Series, Parallel
Circuit diagram and their types : Series and parallel combination of Cells

Capacitance

Capacitance is the ability of a conductor to store electric charge.
In capacitors, if one of the plates of parallel plate capacitor slides, the capacity/capacitance decreases as the overlapping area of the plates changes.
The potential energy stored in a capacitor = 1/2 CV²
Different type of capacitors: Series and parallel combination

Magnetic effect of current and magnetism

Biot-Savart's law describes the magnetic field produced by a current element
The magnetic force on a moving charge is given by F= qVxB .
Ampere's Law gives the relationship between the magnetic field and the current enclosed by a closed loop: ∫B.dl = μ₀I
Magnetic field due to a long straight wire, a coil, solenoid

Electromagnetic Induction

Faraday's law of Induction states that a changing magnetic flux induces an electromotive force (emf) in a circuit.
Lenz's law describes the direction of the induced current, opposing the change in flux.
Motional emf is induced in a conductor moving through a magnetic field
Self-induction describes the emf induced in a coil due to a changing current in the coil (self-inductance L).
Mutual-induction describes the emf induced in one coil due to a changing current in another nearby coil (mutual inductance M)
Transformer- principle , Types, ideal and practical transformers, losses.

Wave Optics

Huygen's principle describes wave propagation
Diffraction occurs when waves encounter an obstacle or an opening
Interference is the combination of two or more waves of the same frequency resulting in either constructive or destructive interference.

Modern Physics

Energy of a photon E = hv, its momentum P = h/λ
Plank's constant & constant speed of light
Photoelectric effect; kinetic energy of emitted electrons,
Bohr's atomic model; energy levels, radius of orbits,
Different series of spectral lines and calculation of energies
Compton effect, matter waves
Nuclear physics: Binding energy of nucleus, fission & fusion, Q-value
Radioactive decay; laws, half-life, mean life etc.,

Fluid Mechanics

Density; specific gravity and relative density
Pressure in fluids and pressure variation with depth and in relation to acceleration.

Thermal Physics

Temperature and various temperature scales
Thermal expansion of solids, liquids, and gases
Thermal conductivity
Heat transfer by conduction, convection, and radiation
Heating effect of electric current
Principle of calorimetry, latent heat and specific heat

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Description

Test your knowledge on measurements and units in physics with this quiz. It covers fundamental and derived quantities, accuracy and precision, and the SI system of units. Perfect for physics students seeking to enhance their understanding.