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3 years ago

An incandescent bulb is supplied with

Physics

1 answer:

Serga [27]3 years ago

8 0

Answer:

Efficiency = 5%

Explanation:

Given that,

Supplies energy to the bulb = 100 J

Transferred energy by the bulb = 5 J

We need to find the efficiency of the bulb. It can be given by "

$\eta=\dfrac{\text{useful energy out}}{\text{useful energy in}}\times 100\\\\=\dfrac{5}{100}\times 100\\\\=5\%$

So, the efficiency of the bulb is 5%.

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Circuit A in a house has a voltage of 208 V and is limited by a 40.0-A circuit breaker. Circuit B is at 120.0 V and has a 20.0-A

Setler79 [48]

Given Information:

Voltage of circuit A = Va = 208 Volts

Current of circuit A = Ia = 40 Amps

Voltage of circuit B = Vb = 120 Volts

Current of circuit B = Ib = 20 Amps

Required Information:

Ratio of power = Pa/Pb = ?

Answer:

Ratio of power = Pa/Pb = 52/15

Explanation:

Power can be calculated using Ohm's law

P = VI

Where V is the voltage and I is the current flowing in the circuit.

The power delivered by circuit A is

Pa = Va*Ia

Pa = 208*40

Pa = 8320 Watts

The power delivered by circuit B is

Pb = Vb*Ib

Pb = 120*20

Pb = 2400 Watts

Therefore, the ratio of the maximum power delivered by circuit A to that delivered by circuit B is

Pa/Pb = 8320/2400

Pa/Pb = 52/15

4 0

3 years ago

A motorcycle and a police car are moving toward one another. The police car emits sound with a frequency of 523 Hz and has a spe

Firdavs [7]

To solve this problem it is necessary to apply the concepts related to Dopler's Law. Dopler describes the change in frequency of a wave in relation to that of an observer who is in motion relative to the Source of the Wave.

It can be described as

$f = \frac{c\pm v_r}{c\pm v_s}f_0$

c = Propagation speed of waves in the medium

$v_r$ = Speed of the receiver relative to the medium

$v_s$ = Speed of the source relative to the medium

$f_0 =$ Frequency emited by the source

The sign depends on whether the receiver or the source approach or move away from each other.

Our values are given by,

$v_s = 32.2m/s \rightarrow$ Velocity of car

$v_r = 14.8 m/s \rightarrow$ velocity of motor

$c = 343m/s \rightarrow$ Velocity of sound

$f_0 = 523Hz \rightarrow$ Frequency emited by the source

Replacing we have that

$f = \frac{c + v_r}{c - v_s}f_0$

$f = \frac{343 + 14.8}{343 - 32}(523)$

$f = 601.7Hz$

Therefore the frequency that hear the motorcyclist is 601.7Hz

8 0

4 years ago

A flat coil of wire consisting of 20 turns, each with an area of 50 cm2, is positioned perpendicularly to a uniform magnetic fie

Nutka1998 [239]

Answer:

i = 0.5 A

Explanation:

As we know that magnetic flux is given as

$\phi = NBA$

here we know that

N = number of turns

B = magnetic field

A = area of the loop

now we know that rate of change in magnetic flux will induce EMF in the coil

so we have

$EMF = NA\frac{dB}{dt}$

now plug in all values to find induced EMF

$EMF = (20)(50 \times 10^{-4})(\frac{6 - 2}{2})$

$EMF = 0.2 volts$

now by ohm's law we have

$current = \frac{EMF}{Resistance}$

$i = \frac{0.2}{0.40} = 0.5 A$

5 0

3 years ago

This is my exam question be serious

elena-s [515]

Answer:

hey answer in the comment section

6 0

3 years ago

water vapor contained in a piston–cylinder assembly undergoes an isothermal expansion at 240°c from a pressure of 7 bar to a pre

mafiozo [28]

The ideal gas constant is a proportionality constant that is added to the ideal gas law to account for pressure (P), volume (V), moles of gas (n), and temperature (T) (R). R, the global gas constant, is 8.314 J/K-1 mol-1.

According to the Ideal Gas Law, a gas's pressure, volume, and temperature may all be compared based on its density or mole value.

The Ideal Gas Law has two fundamental formulas.

PV = nRT, PM = dRT.

P = Atmospheric Pressure

V = Liters of Volume

n = Present Gas Mole Number

R = 0.0821atmLmoL K, the Ideal Gas Law Constant.

T = Kelvin-degree temperature

M stands for Molar Mass of the Gas in grams Mol d for Gas Density in gL.

Learn more about Ideal gas law here-

brainly.com/question/28257995

#SPJ4

7 0

1 year ago