It's the angle made by the incident ray when it's perpendicular to the surface. (Perpendicular lines are the lines that form a graph or like a 90-degree angle)
Answer:
The toy's energy is 18 J.
Explanation:
We have, a 4 kg toy is lifted off the ground and falls at 3 m/s. It is required to find toy's energy.
The toy will have kinetic energy due to its motion. The energy is given by :
So, the toy's energy is 18 J.
At critical temperature, the resistivity of the superconductor
B. It suddenly drops to zero
Explanation:
Materials can be classified into three different types depending on their resistance:
- Conductors: these materials have generally low resistance and allow electricity to pass through easily. The resistance of a conductor increases linearly with the temperature
- Insulators: these materials do not allow electricity to pass through - so they have very high resistance
- Semi-conductors: these are materials that are insulators are room temperature, however they becomes conductors when heated. Therefore, the resistance of a semiconductor decreases when the temperature increases
- Superconductors: these are special materials that are normally conductors; however, at very low temperatures (we are talking about temperature very near to 0 K), their resistance becomes suddenly zero.
Therefore, the correct answer is:
B. It suddenly drops to zero
Learn more about current and resistance:
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The average speed will be 2.38×10⁶ m/sec.The average speed of an object indicates the pace at which it will traverse a distance. The metric unit of speed is the meter per second.
<h3>What is the average speed?</h3>
The total distance traveled by an object divided by the total time taken is the average speed.
The speed calculated at any particular instant of time is known as the instantaneous speed.
Given data;
Distance travelled = 4.12x10¹⁶ meter
Time period= 1.73x10¹⁰ sec
The average speed is found as
Hence, the average speed will be 2.38×10⁶ m/sec.
To learn more about the average speed, refer to the link;
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OK both stars are burning and as they burn they emit electromagnetic radiation (light) and as we move in the light spectrum red comes before blue, so the star that looks red is cooler because as the temperature decreases the colour decreases