Answer:
26
Explanation:
Total power of the circuit
P = V × I = 120 × 20 = 2400 W
Power of each bulb = 90 W
Number of bulbs which work without tripping
N = power of circuit / power of each bulb
N = 2400 / 90
N = 26.66
Number of bulbs should be integer so the number of bulbs be 26.
I'll just find out the path difference between the waves at the starting point. At infinity, the path difference will be zero because the observer will be infinitely far away from both. As the observer goes farther, the path difference keeps reducing till it reaches zero as the observer reaches infinity.
<span>Path difference at starting point = Distance from lower speaker - Distance from upper speaker = √((3)² + (2.5)²) - 2.5 = 1.405 m </span>
<span>Now to find wavelength. </span>
<span>Speed of sound in air at 20 degrees C = 343 m/s </span>
<span>Wavelength = 343 / 686 = 0.5 m </span>
<span>Destructive interference occurs when path difference = (2n + 1)λ/2 where n is an integer. </span>
<span>Maximum n possible can be found by, </span>
<span>(2n + 1)λ/2 < 1.405 </span>
<span>(2n + 1) < (1.4)(2) / (0.5) </span>
<span>2n < 5.6 - 1 </span>
<span>2n < 4.6 </span>
<span>n < 2.3 </span>
<span>So, we have 3 values of n, 0, 1 and 2. </span>
<span>Path differences are, λ/2, 3λ/2 and 5λ/2 which have values 0.25 m , 0.75 m and 1.25 m </span>
<span>But the question asks for distance from starting point. (sheesh!!) </span>
<span>Lets say the observer walked x distance. </span>
<span>Path difference = √((3)² + (2.5 + x)²) - (2.5 + x) </span>
<span>Equate this expression to the values obtained above to get the different values of x. </span>
Electron revolves around the nucleus. Protons, neutrons are called nucleons because they form nucleus of the atom. Quarks are the fundamental particles which combines to form neutrons, protons and other particles.
Hence electron is the answer.
The volume of a cube is given by s^3. So the volume of this block is 3cm x 3cm x3 cm = 27 cm^3.
density = mass/volume =27 g / 27 cm^3 = 1 g/cm^3.
the answer is 1 g/cm^3. I hope this helps!
The period of the wave would be halved