An element whose half-life is 3 years has N atoms. How many atoms would have decayed after 9 years
1 N atoms8
1 N atoms3
2 N atoms3
5 N atoms6
7 N atoms8
Correct answer is E
\(\frac{N}{3}\) = 3years
\(\frac{N}{4}\) = 6years
\(\frac{N}{8}\) = 9years
N - \(\frac{N}{8}\) = \(\frac{7N}{8}\)
Which of the following gives rise to the line spectra obtained from atoms?
Kinetic energy of a moving atom
Potential energy of an electron inside an atom
Change of an electron from a higher to a lower energy level in the atom
Disturbed proton in the nucleus
Excitation of an electron in the atom
Correct answer is C
No explanation has been provided for this answer.
Which of the following statements is correct about cathode rays? They are fast moving
atoms
ions
neutrons
protons
electrons
Correct answer is E
No explanation has been provided for this answer.
0.01Ω
190.91 Ω
200.00 Ω
795.46 Ω
1000.00Ω
Correct answer is C
C1 + C = 2 + 3 = 5μF
q2/4πεor2
q/4πεor2
q2/4πεor
qr/4πεo
4πεoq2r
Correct answer is B
No explanation has been provided for this answer.