Answer:
1.2 × 10^27 neutrons
Explanation:
If one neutron = 1.67 × 10^-27 kg
then in 2kg...the number of neutrons
; 2 ÷ 1.67 × 10^-27
There are.... 1.2 × 10^27 neutrons
Answer:
2.1844 m/s
Explanation:
The principle of conservation of momentum can be applied here.
when two objects interact, the total momentum remains the same provided no external forces are acting.
Consider the whole system , gun and bullet. as an isolated system, so the net momentum is constant. In particular before firing the gun, the net momentum is zero. The conservation of momentum,

assume the bullet goes to right side and the gravitational acceleration =10 
so now the weight of the rifle=

this is a negative velocity to the right side. that means the rifle recoils to the left side
Plant cells are eukaryotic cells that differ in several key aspects from the cells of other eukaryotic organisms. number two sry but Idk
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There are two types of change in matter: physical change and chemical change. ... This is called the Law of Conservation of Matter. It states that matter can never be created or destroyed, only changed and rearranged.
The relationship between the number of visible spectral lines are identical for atoms .However they have unique wavelengths.
Option B
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Explanation:</u>
A spectrum is a range of frequencies or a range of wavelengths. The photon energy of the emitted photon is equal to the difference between two states. For every atom there are quite many electron transitions and each has a energy difference.
This difference in wavelength causes spectrum .As each element emission spectrum is unique because each atom has different energy and causes uniqueness in the emission spectrum . Hence, due to the difference in energy it emits different wavelengths.