Here is your answer
b) 
REASON :
We know that
Velocity= Frequency× Wavelength
So,
Frequency= Velocity/wavelength
Here,
V= 3× 10^8 m/s
Wavelength= 2×10^-3 m
Hence,
Frequency= 3×10^8/2×10^-3
= 3/2 × 10^11
= 1.5× 10^11 Hz
HOPE IT IS USEFUL
Answer:
81.3ohms
Explanation:
Resistance is known to provide opposition to the flow of electric current in an electric circuit.
Power dissipated by the computer is expressed as;
Power = current (I) × Voltage(V)
P = IV... (1)
Note that from ohms law, V = IR
I = V/R ... (2)
Substituting equation 2 into 1, we will have;
P = (V/R)×V
P = V²/R.. (3)
Given source voltage = 100V, Power dissipated = 123W
To get resistance R of the computer, we will substitute the given value into equation 3 to have
123 = 100²/R
R = 100²/123
R = 10,000/123
R = 81.3ohms
The resistance of the computer is 81.3ohms
Answer:
350.72 m/s
Explanation:
Formula for velocity of wave is;
v = fλ
Where;
v is speed
f is frequency
λ is wavelength
We are given;
f = 512 Hz
λ = 0.685 m
Thus;
v = 512 × 0.685
v = 350.72 m/s
A distance of d is covered with 53 mile/hr initially.
Time taken to cover this distance t1 = d/53 hour
Next distance of d is covered with x mile hours.
Time taken to cover this distance t2 = d/x hours.
We have average speed = 26.5 mile / hour
= Total distance traveled/ total time taken
= 
Answer:
Acid mine drainage is dissolved toxic materials wash from mines into nearby lakes and streams.
Explanation:
Acid mine drainage is the flow of acidic water with pH typically between 2 and 4, and high concentrations of other dissolved toxic materials from mines into nearby lakes and streams. It mainly occurs during metal sulfide mining, when the metal sulfide ore such as pyrite (FeS2) is exposed to water and oxygen from air to produce soluble iron and sulfuric acid.
Microorganisms, especially acidophile bacteria like Acidithiobacillus ferrooxidans grow by pyrite oxidation, i.e., oxidizing the Fe²⁺ in pyrite to Fe³⁺, which again react with pyrite and water to produce sulfuric acid. Then the acidic water flows into nearby water sources and reduces the pH value of water in those sources. As a result, heavy metals such as copper, lead, mercury, etc in other mineral ores also get dissolved into the water. The action of acidophile bacteria also increases the rate and degree of acid-mine drainage process.
The acid mine drainage causes water pollution and adversely affect the aquatic plants and animals. It also results in the contamination of drinking water, corrosion of infrastructures such as bridges, etc.
