Answer:
c
Explanation:
Superconductors perform best at very cold temperatures because resistivity of this kind of materials decays drastically with temperature. Chromium is most likely to be the best conductor of electricity because it belongs to the Transition Metal group of the periodic table
Answer: Microwaves
Explanation:
RADAR stands for radio detection and ranging. Radio waves range from 300 GHz to 30 Hz. Modern radar uses higher frequency of waves for detection. These waves are microwaves (300 MHz-300 GHz). Microwaves are types of radio waves and are used in the radar detection.
The electromagnetic wave which has highest frequency is gamma wave but it is not used for radar detection.
Hence, the correct answer is microwaves are the type pf radio waves which have the highest frequency and are used in radar detection.
Answer:
Liquid
Explanation:
Water...
- below 0 degrees Celsius is a solid.
- above 0 degrees Celsius is a liquid.
- above 100 degrees Celsius is a gas.
Answer:
the work is done by the gas on the environment -is W= - 3534.94 J (since the initial pressure is lower than the atmospheric pressure , it needs external work to expand)
Explanation:
assuming ideal gas behaviour of the gas , the equation for ideal gas is
P*V=n*R*T
where
P = absolute pressure
V= volume
T= absolute temperature
n= number of moles of gas
R= ideal gas constant = 8.314 J/mol K
P=n*R*T/V
the work that is done by the gas is calculated through
W=∫pdV= ∫ (n*R*T/V) dV
for an isothermal process T=constant and since the piston is closed vessel also n=constant during the process then denoting 1 and 2 for initial and final state respectively:
W=∫pdV= ∫ (n*R*T/V) dV = n*R*T ∫(1/V) dV = n*R*T * ln (V₂/V₁)
since
P₁=n*R*T/V₁
P₂=n*R*T/V₂
dividing both equations
V₂/V₁ = P₁/P₂
W= n*R*T * ln (V₂/V₁) = n*R*T * ln (P₁/P₂ )
replacing values
P₁=n*R*T/V₁ = 2 moles* 8.314 J/mol K* 300K / 0.1 m3= 49884 Pa
since P₂ = 1 atm = 101325 Pa
W= n*R*T * ln (P₁/P₂ ) = 2 mol * 8.314 J/mol K * 300K * (49884 Pa/101325 Pa) = -3534.94 J
