What is the tangential velocity of a record player which makes 11 revolutions in 20 seconds? Help hello
Answer:
Input impedance of this transformer is 50 ohms.
Explanation:
Given that,
Number of turns in the primary coil, 
Number of turns in the secondary coil, 
Output impedance of the transformer, 
The number of turns and the impedance ratio in the step down transformer is given by :
So, the input impedance of this transformer is 50 ohms. Hence, this is the required solution.
The ancient astronomers think areas of the moon called mares might be Seas.
Option D
<u>Explanation</u>:
The surface area of Earth's moon is dark, large, and is basaltic plains which are formed by ancient volcanic eruptions. They were dubbed as Maria, "ancient astronomers" who misunderstood them as actual seas. They are less reflective than highlands. Due to their iron-rich composition, they tend to appear dark from the naked eye. The Maria cover approximately about 16% of surface mostly on side that is visible from Earth. The few Maria on side that is too far are much smaller and residing mostly in very large craters. The ancient astronomers mistook the surface area as look like actual seas.
The answer is b) false. Stars are mainly classified by their spectra (the elements they absorb) and their temperature.
