Answer:
<h2>
<em>6,142mm²</em></h2>
Explanation:
Given the dimension of a paper measured by a ruler as 7.4 cm wide and 8.3 cm long, the area of the paper is expressed using the area for calculating the area of a rectangle as shown;
Area of the piece of paper = Length * Width
Given length = 7.4cm
Length = 74mm (Since 10mm = 1cm)
Width = 8.3cm
Width (in mm) = 83mm
We converted to mm since the ruler used to measure has a division of 1mm.
Substituting the given values into the formula, we will have:
Area of the piece of paper = 74mm * 83mm
Area of the piece of paper = 6,142mm²
<em>Hence, the area of the piece of paper is 6,142mm²</em>
Answer:
<em>There must be added 500 cm3 of alcohol to bring the concentration to 80%.</em>
Explanation:
<u>Concentration</u>
The concentration of a solution is a measure of the amount of solute that has been dissolved in a given amount of solution.
In the container, there are 2 liters (2000 cubic centimeters) of a solution, 75% of which is alcohol (solute) and 25% of water (solvent).
The original amount of alcohol is:
H = 2000*75% = 1500 cc
The original amount of water is:
W = 2000*25% = 500 cc
When we add x cc of pure alcohol, there are 1500+x cc of alcohol out of 2000+x cc of solution.
The new concentration is calculated as:
And it's known this concentration is 80% (0.8), thus:
Multiplying by 2000+x:
Operating:
Rearranging:
x= 500
There must be added 500 cm3 of alcohol to bring the concentration to 80%
<span>The correct option is B): meters A and C. In fact, both A and C are ammeters. An ammeter is a device used to measure the current in a branch of a circuit. In order to work properly, an ammeter should be connected in series to a resistor, in order to have the same amount of current that passes through the resistor. In this circuit, we see that devices A and C are both connected in series to a resistor, so they are ammeters. Instead, devices B and D are connected in parallel, so they do not measure the current but the voltage (in fact, they are called voltmeter).</span>
Answer:
The power is found to be P = 14250600 W
Explanation:
First we find the voltage or potential difference at the position:
Voltage = Amplitude of Field x Distance
Voltage = V = (0.9 V/m)(42000 m)
V = 37800 volts
Now, we know the formula of electric power is:
Power = Voltage x Current
P = V I
but, from Ohm's Law:
V = I R
I = V/R
Therefore,
P = V²/R
Resistance = real part of impedence = 377 Ω
Therefore,
P = (37800 V)(377 Ω)
<u>P = 14250600 W</u>