Answer:
a. wavelength of the sound, 
b. observed frequecy, 
Given:
speed of sound source,
= 80 m/s
speed of sound in air or vacuum,
= 343 m/s
speed of sound observed,
= 0 m/s
Solution:
From the relation:
v =
(1)
where
v = velocity of sound
= observed frequency of sound
= wavelength
(a) The wavelength of the sound between source and the listener is given by:
(2)
(b) The observed frequency is given by:


(3)
Using eqn (2) and (3):


Answer:
a circuit is a complete loop that carries a current in the form of electrons from negative to positive
Explanation:
The difference between current and circuit is that a circuit is a complete loop that carries a current in the form of electrons from negative to positive
.
In a circuit, there are difference elements or components such as the battery, wire, resistor. The goal of a circuit arrangement is to completely carry current from one end to another.
The current is the quantity of charge that flows within the circuit per unit of time.
So, the battery supplies the electromotive force to move the current round the circuit.
Your answer would be C, "By conserving energy"! A gas can do work through something called the First Law of Thermodynamics. Heat that energy used by the gas during this "work" cannot be created or destroyed however it can be transferred and converted. This energy can only be stored during these processes, not removed. An example of this would be gas in a cylindrical object such as a piston. When the gas is heated, it expands and moves the piston upwards. When it expands, it stores that energy it gains through the heat given.
I hope this helps! (: