Physics Trivia: Practice Questions On Electricity And Energy!

Explanation
The potential difference required to pass a current through a wire is determined by Ohm's Law, which states that the potential difference (V) is equal to the current (I) multiplied by the resistance (R). In this case, the current is 0.2 A and the resistance is 20 ohm. Therefore, the potential difference can be calculated as V = I * R = 0.2 * 20 = 4 V.

Explanation
When two electric bulbs are joined in series, the total resistance is the sum of the individual resistances. In this case, since the resistances are in the ratio 1:2, the total resistance will also be in the ratio 1:2. According to Ohm's law, the energy consumed in a circuit is directly proportional to the resistance. Therefore, when the resistances are in the ratio 1:2, the energy consumed will also be in the ratio 1:2. Hence, the correct answer is 1:2.

Explanation
The correct answer is electric energy. A kilowatt-hour is a unit of measurement used to quantify the amount of electric energy consumed or produced over a period of time. It is commonly used to measure the energy consumption of household appliances or the electricity generated by power plants. This unit takes into account both the power (measured in kilowatts) and the duration of usage (measured in hours), providing a measure of the total energy consumed or produced. Therefore, electric energy is the appropriate unit for measuring kilowatt-hour.

Explanation
Black surfaces absorb more heat than any other surface under identical conditions because they have a higher absorption rate for all wavelengths of light. When light hits a black surface, it is absorbed rather than reflected, converting the light energy into heat. This is why black surfaces can feel hotter to the touch compared to lighter-colored surfaces, as they are able to absorb and retain more heat energy.

Explanation
The atomic number of an element represents the number of protons in the nucleus of an atom. Natural radioactive elements typically have a higher atomic number, indicating that they have more than 82 protons. This is because elements with higher atomic numbers tend to be more unstable and therefore more likely to undergo radioactive decay.

Explanation
The given answer, "current = resistance x potential difference," does not represent Ohm's law. Ohm's law states that the current flowing through a conductor is directly proportional to the potential difference across it, and inversely proportional to the resistance of the conductor. The correct representation of Ohm's law is "current = potential difference / resistance," which is not included in the given options.

Explanation
When measuring potential difference using a voltmeter, the current is expected to be very low or negligible. Therefore, to measure the current accurately, an ammeter is used instead. The ammeter is designed to handle higher currents and is connected in series with the circuit to measure the flow of current.

Explanation
The correct answer is "Non-conventional source" because the question is asking for a term that is the opposite of "conventional source of energy." Since a power plant is considered a conventional source of energy, the term that would be the opposite or alternative to it is a non-conventional source of energy. Solar energy is an example of a non-conventional source of energy as it is derived from sunlight and is considered renewable and environmentally friendly.

Explanation
The correct answer is solar energy because it is listed twice in the given options, which indicates a duplication error. The other sources of energy listed, such as wind energy, hydroelectric power, and tidal energy, are unique and do not have any repetition.