Answer:
70 m.
Explanation:
Given,
Frequency, f = 20 HZ
speed of sound, v = 1400 m/s
wavelength of the waves = ?
we know,
v = f λ



Hence, the wavelength of the wave is equal to 70 m.
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Answer:
Explanation:
When the number of slits increases, the intensity of fringes increases.
So, the fringes appear to be more bright.
As we know that the fringe width is inversely proportional to the number of slits, so as the number of slits increases, the fringe width decreases, hence the fringes are narrower, bright and close together.
Answer: The correct answer is option (D).
Explanation:
Voltmeter is a device which measures the the voltage applied across the circuit. It is an electrical instrument used to measure the electric potential between the two points in an electric circuit.
Where as:
A switch is the device which used to connect or disconnect the circuit.
Resistor is a device which opposes the flow of current is an electric circuit.
An ammeter the is an electrical device which measures the amount of current in flowing in amperes in an electrical circuit
Hence,the correct answer is option (D).
Answer:
Option D
Explanation:
Resistors are said to be connected in “Series”, when they are daisy chained together in a single line. Since all the current flowing through the first resistor has no other way to go it must also pass through the second resistor and the third and so on. Then, resistors in series have a Common Current flowing through them as the current that flows through one resistor must also flow through the others as it can only take one path.
Total Resistance = R₁ + R₂ +R₃ +R₄ ohm
Note then that the total or equivalent resistance, R has the same effect on the circuit as the original combination of resistors as it is the algebraic sum of the individual resistances.
Total resistance R = 3 + 3 + 3 +3
= 12 ohm