The resistance of the lamp is apparently 50V/2A = 25 ohms.
When the circuit is fed with more than 50V, we want to add
another resistor in series with the 25-ohm lamp so that the
current through the combination will be 2A.
In order for 200V to cause 2A of current, the total resistance
must be 200V/2A = 100 ohms.
The lamp provides 25 ohms, so we want to add another 75 ohms
in series with the lamp. Then the total resistance of the circuit is
(75 + 25) = 100 ohms, and the current is 200V/100 ohms = 2 Amps.
The power delivered by the 200V mains is (200V) x (2A) = 400 watts.
The lamp dissipates ( I² · R ) = (2² · 25 ohms) = 100 watts.
The extra resistor dissipates ( I² · R) = (2² · 75 ohms) = 300 watts.
Together, they add up to the 400 watts delivered by the mains.
CAUTION:
300 watts is an awful lot of power for a resistor to dissipate !
Those little striped jobbies can't do it.
It has to be a special 'power resistor'.
300 watts is even an unusually big power resistor.
If this story actually happened, it would be cheaper, easier,
and safer to get three more of the same kind of lamp, and
connect THOSE in series for 100 ohms. Then at least the
power would all be going to provide some light, and not just
wasted to heat the room with a big moose resistor that's too
hot to touch.
Constructive interference of two coherent waves will occur if the path difference is λ/2.
<h3>Constructive interference:</h3>
When two waves are in phase and their maxima add, a process known as constructive interference occurs where the combined amplitude of the two waves equals the sum of their individual amplitudes.
The resultant wave is created by adding the amplitudes of two waves that are in phase and traveling in the same direction. The waves in this instance are said to have experienced beneficial interference. The upward displacement of the medium is higher than the displacement of the two interfering pulses because upward displacement occurs when the waves experience constructive interference. When the phase difference between the waves is an even multiple of (180°), constructive interference happens.
Learn more about constructive interference here:
brainly.com/question/17329186
#SPJ4
The correct option is B.
Sunglasses are designed to block polarized light. If you are driving toward the sun, most of the sun's glare will be coming to you horizontally, thus, the best sunglasses to wear is the one, that will block the horizontal glare and allow only the vertical glare to pass through.
Answer:
1 and 3
Explanation:
<u>1 and 3 </u>
Increasing coils increases strength
COOLING the wire would increase current flow and strength of magnet
Adding an iron core will definitely increase the strength of the electromagnet
