The first one is C. Hope this helps!! If you need anymore help just message me and I will try to get back to you quickly and help in any way i can!
Answer:
52
Explanation:
Tellurium is the element of the periodic table with atomic number 52.
The atomic number of a chemical element represents the number of atoms contained in the nucleus of the atom: therefore, this means that an atom of tellurium contains exactly 52 protons in its nucleus.
Tellurium is classified as a metalloid, having properties in between metals and non-metals, and it appears with a silver color.
Explanation:
It is given that, the range of human hearing is roughly from twenty hertz to twenty kilohertz.
Minimum frequency, f = 20 Hz
Maximum frequency, f' = 20,000 Hz
We need to find the lengths of the longest and shortest pipes. For open pipes, the length of pipe is given by :

For shortest pipe, frequency should be maximum, 
l = 0.008575 m
For longest pipe, frequency should be minimum, 
l' = 8.575 m
So, the lengths of longest and shortest pipes are 8.575 meters and 0.008575 meters respectively.
Answer: The heat capacity and the specific heat are related by C=cm or c=C/m. The mass m, specific heat c, change in temperature ΔT, and heat added (or subtracted) Q are related by the equation: Q=mcΔT. Values of specific heat are dependent on the properties and phase of a given substance.
Explanation: