He was the first to improve the telescope i believe
............................................................................... Hello wonderful person <3
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:

Explanation:
Wien's displacement law states that the radiation of the black body curve for different temperatures will give peak values at different wavelengths and this wavelength is related inversely to the temperature.
Formally the law of Wien displacement states that the black body's spectral radiation per unit of wavelength, will give peaks at the wavelength of
which is given by the mathematical expression.
Here, b is proportionality constant with value of
The wavelength of the peak of the Gaussian curve is inversely related to temperature in degree kelvin.