Explanation

Einstein’s photoelectric equation is "hv = hvo + (1/2 mv^2) max", where:

• hv is the energy of the incident photon
• h is Planck's constant
• vo is the threshold frequency
• m is the mass of the emitted photoelectron
• max is the maximum kinetic energy of the emitted photoelectron.

Explanation

The property that doesn't typically apply to solids is "Solids have an indefinite volume."

Explanation

In a fusion reactor, it is necessary to overcome the electrostatic repulsive force between nuclides (nuclei) in order to achieve fusion. This requires:

• Very high temperature: Fusion reactions occur at extremely high temperatures, typically around 150 million degrees Celsius (270 million degrees Fahrenheit). This energy is needed to overcome the electrostatic repulsive force and bring the nuclei close enough together to fuse.
• Very high pressure: Fusion reactions also require incredibly high pressure, similar to those found at the core of the sun. This pressure helps to overcome the repulsive force and increase the likelihood of fusion.
• Very small volume: The reaction chamber in a fusion reactor is designed to be extremely small, which helps to increase the density of the plasma (ionized gas) and reduce the distance between the nuclei. This makes it easier to overcome the electrostatic repulsive force and achieve fusion.

Explanation

Increasing the number of slits on a diffraction grating will increase the intensity of the central maximum of the diffraction pattern.

Explanation

• The energy received from the sun on earth is proportional to the square of the temperature of the sun (Stefan-Boltzmann law). If the temperature of the sun is doubled, the energy received on earth will increase by a factor of 2^2 = 4. 
• However, since the energy is also proportional to the square of the radius of the sun, and the radius remains constant, the total increase in energy received is 4^2 = 16.
• So, if the temperature of the sun is doubled, the rate of energy received on earth will be increased by a factor of 16.

Explanation

• The rate of cooling of a body is typically faster at higher temperatures and slows down as the temperature difference between the body and its surroundings decreases. This behavior is governed by Newton's law of cooling.
• Given that the body cools from 90°C to 80°C in 5 minutes, we can infer that the rate of cooling will be slower when the temperature difference is smaller, such as when cooling from 70°C to 60°C.