Answer:
4589.05 year
Explanation:
The relation of activity is given by
we have given
Half life 
We know that half life 

So 



Q9. R₁ only.
Since the upper branch is cut at x, the circuit in this branch is not closed. No current will flow through this branch. In this case, the circuit becomes a series circuit and current only flows through R₁.
Q10. 3 pathways.
3 different resistors are connected in parallel, which means there will be three branches of parallel circuit, each with one resistor. Current can flow through 3 different branches, until the parallel circuits combine together again.
Answer:
Visible light
X rays
ultraviolet radiation
gamma rays
microwave radiation
Explanation:
Electromagnetic waves consist of oscillating electric and magnetic fields which vibrate in a direction perpendicular to the direction of motion of the wave (transverse wave). Electromagnetic waves have all same speed in a vacuum (
, known as speed of light) and are classified into 7 different types according to their frequency and wavelength. This classification is called electromagnetic spectrum.
From lowest to highest wavelength, the 7 types are:
Gamma rays
X-rays
Ultraviolet radiation
Visible light
Infrared radiation
Microwaves
Radio waves
Sound waves, on the contrary, do not belong to the electromagnetic spectrum, since they are another type of wave called mechanical waves (which consist of vibrations of the particles in a medium).
Answer:
(1)
(2)
but
transition not allowed.
Explanation:
Atoms can be described by the quantum number n, spin quantum number S, angular momentum quantum number L, and total angular momentum quantum number J. Based on approximation Russel- Saunders electron coupling, the atomic term symbol can be written as
.
The conditions or selection rule to promoting the electron are discussed below:
(1) The total spin should not change that is
.
(2) The total angular momentum change should be,
but
transition not allowed.