C: the mechanical energy isn't conserved. Some energy was lost to friction.
Answer:
It is easier to hear a musician in the classroom than outdoors
Explanation:
It is easier to hear a musician in the classroom due to the improved acoustics provided by the walls of the classroom whereby along with the direct sound of the musician, which is the lead source of the sounds, there is an increased number of indirect sound reaching the ear in the classroom than outdoors and due to precedence effect, all the sound appear to come from the musician
In music played outside, along side the direct sound from the musician, the indirect sound that reach the ear is echoed from maybe by only the ground while the majority of the sound from the music wanders away with the wind and in other directions as well as being absorbed such that speakers will be required to improve the sound of the music outdoors.
Answer:
Explanation:
It is given that,
Initially, the electron is in n = 7 energy level. When it relaxes to a lower energy level, emitting light of 397 nm. We need to find the value of n for the level to which the electron relaxed. It can be calculate using the formula as :
R = Rydberg constant, 
Solving above equation we get the value of final n is,
or
So, it will relax in the n = 2. Hence, this is the required solution.
Answer:
Sodium is stored under paraffin oil
Explanation:
Group 1 metals are known to be very highly reactive. The chemical reactivity of the members of the group decreases down the group.
Sodium reacts violently with water and upon exposure to the atmosphere. As a result of this, it must be stored under paraffin oil.
A block and tackle or only tackle is a system of two or more pulleys with a rope or cable threaded between them, usually used to lift heavy loads.
