All categories

4 years ago

A 150-W lamp is placed into a 120-V ac outlet. What is the peak current?

Physics

2 answers:

Sidana [21]4 years ago

8 0

This question is about as sneaky as they ever get.

First let's do the easy part:

Power = (voltage) x (current)

150 watts = (120 volts) x (current)

current = (150 watts) / (120 volts)

current = 1.25 Amperes but this is NOT the answer to the question.

The voltage at the outlet is a "sinusoidal" wave ... it wiggles up and down 60 times every second. The number of "120 volts" is NOT the "peak" of the wave. In fact , the highest it ever gets is √2 greater than 120 volts. And all of this applies to the current too.

The RMS current through the lamp is (150/120) = 1.25 Amperes .

The peak current through the lamp is 1.25·√2 = about 1.77 Amperes .

devlian [24]4 years ago

3 0

Answer:

Explanation:

Formula

W = I * E

Givens

W = 150

E = 120

I = ?

Solution

150 = I * 120 Divide by 120

150/120 = I

5/4 = I

I = 1.25

Note: This is an edited note. You have to assume that 120 is the RMS voltage in order to go any further. That means that the peak voltage is √2 times the size of 120. The current has the same note applied to it. If the voltage is its rms value, then the current must (assuming the properties of the bulb do not change)

On the other hand, if the voltage is the peak value at 120 then 1.25 will be correct.

However I would go with the other answerer's post and multiply both values by √2

You might be interested in

The velocity of the wave involved in the Doppler effect:

Margarita [4]

The Doppler Effect provides the equation for the calculation of apparent frequency:

f=fo[vo/(vo-vr)]

where:
vo=source wave velocity
vr=relative speed between source and observer
f=apparent frequency
fo=source frequency

The velocity of the doppler wave is
v=λf

where λ is light wavelength. Hence,

v=λfo[vo/(vo-vr)]

Based on the equation, we can say that wave velocity will always be defined by one and only one wavelength.

Therefore the answer is letter C.

4 0

3 years ago

Read 2 more answers

A rocket moves upward from rest with an acceleration of 40 m/s2 for 5 seconds. It then runs out of fuel and continues to move up

Snezhnost [94]

Answer:

Maximum height of rocket = 2538.74 m

Explanation:

We have equation of motion s = ut + 0.5 at²

For first 5 seconds

s = 0 x 5 + 0.5 x 40 x 5² = 500 m

Now let us find out time after 5 seconds rocket move upward.

We have the equation of motion v = u + at

After 5 seconds velocity of rocket

v = 0 + 40 x 5 = 200 m/s

After 5 seconds the velocity reduces 9.8m/s per second due to gravity.

Time of flying after 5 seconds

$t=\frac{200}{9.81}=20.38s$

Distance traveled in this 20.38 s

s = 200 x 20.38 - 0.5 x 9.81 x 20.38² = 2038.74 m

Maximum height of rocket = 500 +2038.74 = 2538.74 m

6 0

3 years ago

A 15x10^-6c charge is placed at the origin and a 9x10^-6C charge is placed on the x-axis at x=1.00m. where, on the x-axis is the

Harlamova29_29 [7]

The Electric field is zero at a distance 2.492 cm from the origin.

Let A be point where the charge $15\times10^-6$ C is placed which is the origin.

Let B be the point where the charge $9\times 10^-6$ C is placed. Given that B is at a distance 1 cm from the origin.

Both the charges are positive. But charge at origin is greater than that of B. So we can conclude that the point on the x-axis where the electric field = 0 is after B on x - axis.

i.e., at distance 'x' from B.

Using Coulomb's law, $\frac{kQ_A^2}{d_A^2} = \frac{kQ_B^2}{d_B^2}$ ,

$Q_A$ = $15\times 10^-6 C$

$Q_B=9\times10^-6C$

$d_A = 1+x cm$

$d_B=x cm$

k is the Coulomb's law constant.

On substituting the values into the above equation, we get,

$\frac{(15\times10^-6)^2}{(1+x)^2} =\frac{(9\times10^-6)^2}{x^2}$

Taking square roots on both sides and simplifying and solving for x, we get,

1.67x = 1+x

Therefore, x = 1.492 cm

Hence the electric field is zero at a distance 1+1.492 = 2.492 cm from the origin.

Learn more about Electric fields and Coulomb's Law at brainly.com/question/506926

#SPJ4

3 0

1 year ago

The car has a mass of 0·50 kg. The boy

PIT_PIT [208]

Answer:

A solenoid is a type of electromagnet, the purpose of which is to generate a controlled magnetic field through a coil wound into a tightly packed helix. The coil can be arranged to produce a uniform magnetic field in a volume of space when an electric current is passed through it.

7 0

3 years ago

The graph shows the range of frequencies commonly heard by some animals.

Vsevolod [243]

Concept:

Frequency- It is defined as the number of oscillations occur in one second.

Its SI unit is Hertz (Hz)

Given: Produced sound vibrations is 18,500 cycles in 0.75 seconds

∵ In 0.75 second, produced sound has oscillations = 18,500 cycles

∴ In 1.0 second, produced sound has oscillations = (18,500 ÷ 0.75) Hz

The frequency of the sound will be ≈ 24,667 Hz

From the study of the given graph, only the animals (c) Cats, (b) Moths and (a) Bats can hear the produced sound because their upper audible frequency range is greater than 24,667 Hz.

3 0

3 years ago

Read 2 more answers