Answer:
(1) 0.333 Hz
(2) 4 sec
(3) 2 sec, 0.5 Hz
Explanation:
(1) We have given time period of pendulum is 3 sec
So T = 3 sec
Frequency will be equal to 
(2) Frequency of the pendulum is given f = 0.25 Hz
Time period is equal to 
(3) It is given that a pendulum makes 10 back and forth swings in 20 seconds
So time taken to complete 1 back and forth swings = 
So time period T = 2 sec
Frequency will be equal to 
Answer:
Chemical composition, Temperature, Radial velocity, Size or diameter of the star, Rotation.
Explanation:
Elemental abundances are determined by analyzing the relative strengths of the absorption lines in the spectrum of a star.
The Spectral class to which the star belongs gives the information related to the temperature of the star. It is the spectral lines that determine the spectral class O B A F G K M are the spectral classes.
By measuring the wavelengths of the lines in the star's spectrum gives the radial velocity. Doppler shift is the method used to find the radial velocity.
A star can be classified as a giant or a dwarf . A giant star will have narrow width spectral lines whereas a dwarf star has wider spectral lines.
Broadening of the spectral lines will determine the star's rotation.
The loudness of sound refer to how loud or soft a sound seems to a listener
