Answer : The amount of heat needed is, 1188 J
Explanation :
Formula used :

where,
q = heat needed = ?
m = mass of copper = 55 g
c = specific heat capacity of copper = 
= initial temperature = 
= final temperature = 
Now put all the given values in the above formula, we get:


Thus, the amount of heat needed is, 1188 J
Answer: v = 2π2 Kme2 Z / nh
Explanation:
The formula for velocity of an electron in the nth orbit is given as,
v = 2π2 Kme2 Z / nh
v = velocity
K = 1/(4πε0)
m= mass of an electron
e = Charge on an electron
Z= atomic number
h= Planck’s constant
n is a positive integer.
Answer:
C
Explanation:
You would be correct in guessing C as in a chemical formula symbol of each element is stated.
Like Salt is Sodium Chloride, and its chemical formula is NaCl (Na=sodium, Cl= chloride)
<u>Answer:</u>
The correct answer option is C. 2.
<u>Explanation:</u>
We are given the number '0.0020' and we are to indicate the number of significant figures in the given measured number.
According to the rules of significant figures, numbers that are non-zero, zeros between any two significant numbers and the ending zeros in the decimal position are categorized as significant figures.
Since there is one non-zero number and one ending zero in the decimal position, therefore 0.0020 has 2 significant figures.