Answer:
The temperature of silver at this given resistivity is 2971.1 ⁰C
Explanation:
The resistivity of silver is calculated as follows;
![R_t = R_o[1 + \alpha(T-T_o)]\\\\](https://tex.z-dn.net/?f=R_t%20%3D%20R_o%5B1%20%2B%20%5Calpha%28T-T_o%29%5D%5C%5C%5C%5C)
where;
Rt is the resistivity of silver at the given temperature
Ro is the resistivity of silver at room temperature
α is the temperature coefficient of resistance
To is the room temperature
T is the temperature at which the resistivity of silver will be two times the resistivity of iron at room temperature
![R_t = R_o[1 + \alpha(T-T_o)]\\\\\R_t = 1.59*10^{-8}[1 + 0.0038(T-20)]](https://tex.z-dn.net/?f=R_t%20%3D%20R_o%5B1%20%2B%20%5Calpha%28T-T_o%29%5D%5C%5C%5C%5C%5CR_t%20%3D%201.59%2A10%5E%7B-8%7D%5B1%20%2B%200.0038%28T-20%29%5D)
Resistivity of iron at room temperature = 9.71 x 10⁻⁸ ohm.m
When silver's resistivity becomes 2 times the resistivity of iron, we will have the following equations;
![R_t,_{silver} = 2R_o,_{iron}\\\\1.59*10^{-8}[1 + 0.0038(T-20)] =(2 *9.71*10^{-8})\\\\\ \ (divide \ through \ by \ 1.59*10^{-8})\\\\1 + 0.0038(T-20) = 12.214\\\\1 + 0.0038T - 0.076 = 12.214\\\\0.0038T +0.924 = 12.214\\\\0.0038T = 12.214 - 0.924\\\\0.0038T = 11.29\\\\T = \frac{11.29}{0.0038} \\\\T = 2971.1 \ ^0C](https://tex.z-dn.net/?f=R_t%2C_%7Bsilver%7D%20%3D%202R_o%2C_%7Biron%7D%5C%5C%5C%5C1.59%2A10%5E%7B-8%7D%5B1%20%2B%200.0038%28T-20%29%5D%20%3D%282%20%2A9.71%2A10%5E%7B-8%7D%29%5C%5C%5C%5C%5C%20%5C%20%28divide%20%5C%20through%20%5C%20by%20%5C%201.59%2A10%5E%7B-8%7D%29%5C%5C%5C%5C1%20%2B%200.0038%28T-20%29%20%3D%2012.214%5C%5C%5C%5C1%20%2B%200.0038T%20-%200.076%20%3D%2012.214%5C%5C%5C%5C0.0038T%20%2B0.924%20%3D%2012.214%5C%5C%5C%5C0.0038T%20%20%3D%2012.214%20-%200.924%5C%5C%5C%5C0.0038T%20%3D%2011.29%5C%5C%5C%5CT%20%3D%20%5Cfrac%7B11.29%7D%7B0.0038%7D%20%5C%5C%5C%5CT%20%3D%202971.1%20%5C%20%5E0C)
Therefore, the temperature of silver at this given resistivity is 2971.1 ⁰C
300,000+70,000+3,000+600+90+8
Answer:
Từ ánh sáng từ mặt trời đến nhiệt liên tục phát ra từ cơ thể chúng ta, có nhiều dạng bức xạ khác nhau. Tuy nhiên, khi nói đến bức xạ và nguy cơ ung thư, hầu hết mọi người đều nghĩ đến tia X và tia gamma.
Các nguồn tự nhiên của tia X và tia gamma bao gồm khí radon, chất phóng xạ trong lòng đất và các tia vũ trụ tấn công hành tinh từ không gian. Tuy nhiên, loại bức xạ này cũng có thể do con người gây ra. Tia X và tia gamma được sản xuất trong các nhà máy điện hạt nhân để sử dụng trong các xét nghiệm hình ảnh y tế, điều trị ung thư, chiếu xạ thực phẩm và máy quét an ninh sân bay với liều lượng nhỏ.
English:
From light from the sun to the heat that is continuously emitted from our bodies, there are many different forms of radiation. However, when it comes to radiation and cancer risk, most people think of X-rays and gamma rays.
Natural sources of X-rays and gamma rays include radon gas, underground radioactive material, and cosmic rays that strike the planet from space. However, this type of radiation can also be caused by humans. X-rays and gamma rays are produced in nuclear power plants for use in medical imaging tests, cancer treatments, food irradiation and airport security scanners in small doses.
Answer:
29274.93096 m/s
Explanation:
= Distance at perihelion = 
= Distance at aphelion = 
= Velocity at perihelion = 
= Velocity at aphelion
m = Mass of the Earth = 5.98 × 10²⁴ kg
M = Mass of Sun = 
Here, the angular momentum is conserved
Earth's orbital speed at aphelion is 29274.93096 m/s
Kinetic energy is given by
Kinetic energy at perihelion is
Potential energy is given by
Potential energy at perihelion is
Kinetic energy at aphelion is
Potential energy is given by
Potential energy at aphelion is 
