Longitudinal waves, such as sound waves, travel faster in solids because particles in solids are more tightly packed.

Magnets primarily attract ferromagnetic materials like iron and steel.

If two masses have the same speed, their momenta can differ if they move in different directions.

The main characteristics of a wave are its wavelength, frequency, and speed.

According to Coulomb’s law, the force between charges increases by a factor of four when the distance is halved.

Moving charges generate magnetic fields.

Kilowatt-hour (kWh) is a unit of energy, representing the energy used when 1 kilowatt of power is consumed over 1 hour.

Efficiency = Output Power / Input Power. If the bulb is 50% efficient and its input power is 20W, then Output Power = 0.5 × 20W = 10W.

When a charged object is brought near an uncharged conductor, the nearer end acquires an opposite charge due to electrostatic induction.

According to Faraday’s Law of Electromagnetic Induction, an emf is induced in a circuit when the magnetic flux through the circuit changes.

A cylindrical Gaussian surface is used to calculate the electric field of a line charge, as it matches the symmetry of the field.

Wavelength is the distance a wave travels during one complete cycle.

Since the wall does not move, no work is done as there is no displacement.

In the right-hand rule for rotational motion, the curl of the fingers of the right hand represents the direction of the angular displacement.

Gamma radiation emission does not change the mass number or atomic number.

When a positron and electron annihilate, they produce two gamma-ray photons.

As the magnet falls through the copper tube, eddy currents are induced in the copper, which generate magnetic fields that oppose the motion of the magnet, thus reducing its acceleration to less than the acceleration due to gravity.

A diffraction grating is used in a spectrometer to separate light into its component wavelengths with higher precision.

Radioisotopes can be formed by neutron bombardment, as the neutron can be absorbed by the nucleus, making it unstable and radioactive.

In a uniformly charged conducting sphere, the electric potential is constant throughout the conductor and equal to the potential at the surface.

The speed of sound is faster in moist air because moist air has a lower density than dry air, allowing sound to travel faster.

Power is calculated as work done divided by time: 140,000 J/70 s = 2 kilowatts.

The emf produced by a generator is maximized when the plane of the coil is perpendicular to the magnetic field, as this leads to the greatest rate of change of magnetic flux.

Magnetic flux is zero when the magnetic field is perpendicular to the surface, i.e., at 90 degrees.

A filter is used in power supply circuits to smooth the pulsating output from a rectifier. It typically consists of capacitors and inductors that reduce the ripple voltage and provide a more stable DC output.

Newton’s third law of motion explains the existence of a pair of forces in nature.

The plates of a capacitor are separated by an insulating material (dielectric), preventing direct electrical contact while allowing charge storage.

The minute hand of a clock is a good example of uniform circular motion, as it moves at a constant speed in a circle.

Pumping more air molecules into the tire increases the number of collisions per second with the walls, raising pressure.

The Compton scattering equation refers to a change in wavelength, which is a unit of length.

The internal resistance of a battery arises due to the electrolyte resisting ion flow.

Ohmic devices follow Ohm’s Law, where the current is directly proportional to the applied voltage, and the resistance remains constant over a range of voltages. Copper wire is an example of such a device.

Capacitors store potential energy in their electric fields.

When a body moves in a straight line, its displacement is equal to the distance traveled.

Centripetal force is a type of force and is measured in Newtons in the SI system.

The maximum emf induced in a rotating coil in a magnetic field is given by the equation: emf_max = NBAω. The resistance of the coil does not affect the maximum induced emf, as emf depends on the rate of change of the magnetic flux.

From 400 to 50 counts, the reduction occurs through three half-lives. Therefore, 150 minutes / 3 half-lives = 50 minutes per half-life.

The increase in kinetic energy is calculated using momentum and kinetic energy formulas.

Using the free fall equation, the time for a stone to fall from 80 m is approximately 4 seconds.

Force and acceleration always have the same direction, following Newton’s second law.

Stationary waves form a standing pattern and do not transport energy or mass, unlike traveling waves.

After 7 seconds, the ratio of amplitude to displacement for a second pendulum is 1:2.

Air friction (drag) acts against the motion of a projectile in both horizontal and vertical directions, reducing its horizontal range and altering its vertical trajectory.

Fillings in teeth should expand at the same rate as the tooth to avoid cracking.

The force acting on a charged particle in an electric field depends on the charge and electric field, not on the particle’s speed.

The photoelectric effect demonstrates the particle nature of light. When light shines on a metal surface, it ejects electrons, which can only be explained if light consists of photons.

Using conservation of energy, the maximum velocity of the swing is calculated based on the change in potential energy between the highest and lowest points.

The temperature coefficient of resistance measures how much a material’s resistance changes per degree Kelvin.

The angular speed of the minute hand is 12 times greater than the hour hand’s.

In a transformer, the coils are magnetically linked through mutual magnetic induction, where a changing current in one coil induces a voltage in the other.

The kinetic energy becomes twice the potential energy when the displacement is 1/√3 of the maximum amplitude.

The electric field intensity increases by a factor of four when the distance is halved.

Thermal equilibrium is achieved through heat flow between objects until they reach the same temperature.

Gamma rays are emitted during nuclear transitions, not electronic transitions, which emit infrared, ultraviolet, or visible light.