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Katarina [22]
2 years ago
13

The operating temperature of a tungsten filament in an incandescent light bulb is 2450 K, and its emissivity is 0.350. Find the

surface area of the filament of a 150 W bulb if all the electrical energy consumed by the bulb is radiated by the filament as electromagnetic waves. (Only a fraction of the radiation ap- pears as visible light.)
Physics
1 answer:
laila [671]2 years ago
8 0

Answer:

A = 2.1 × 10^(-4) m²

Explanation:

We are given;

Temperature; T = 2450 K

Emissivity; ε = 0.35

Bulb rating; H = 150 W

To calculate the surface area, we will use the formula;

H = AεσT⁴

Where σ is stephan boltzman constant with a value of 5.66 × 10^(−8) W/m²⋅K⁴

Making A the subject of the formula, we have;

A = H/εσT⁴

Plugging in the relevant values gives;

A = 150/(0.35 × 5.66 × 10^(−8) × 2450⁴)

A = 2.1 × 10^(-4) m²

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Motor oil , with a viscosity of 0 . 250 Ns / m2 , is flowing through a tube that has a radius of 5 . 00 mm and is 25 . 0 cm long
Thepotemich [5.8K]

Answer:

1.1775 x 10^-3 m^3 /s

Explanation:

viscosity, η = 0.250 Ns/m^2

radius, r = 5 mm = 5 x 10^-3 m

length, l = 25 cm = 0.25 m

Pressure, P = 300 kPa = 300000 Pa

According to the Poisuellie's formula

Volume flow per unit time is

V=\frac{\pi \times Pr^{4}}{8\eta l}

V=\frac{3.14 \times 300000\times \left ( 5\times 10^{-3} \right )^{4}}{8\times 0.250\times 0.25}

V = 1.1775 x 10^-3 m^3 /s

Thus, the volume of oil flowing per second is 1.1775 x 10^-3 m^3 /s.

3 0
2 years ago
The wavelength of light mainly affects our perception of
s2008m [1.1K]

Answer:

I would think the answer is color, if the wavelength is within the visible light spectrum. This could be answered in different ways but I'm pretty sure the answer you are looking for is hue/color.

6 0
3 years ago
To heat the house, the boiler transfers 15 MJ of energy in 10 minutes.
Harrizon [31]

The formula is P = E/t, where P means power in watts, E means energy j , and t means time in seconds. This formula states that power is the consumption of energy per unit of time.

P = 15 M / 10*60

M = mega = 10⁶

15 *10⁶ / 600

= 25000 watt

8 0
2 years ago
A 91.5 kg football player running east at 3.73 m/s tackles a 63.5 kg player running east at 3.09 m/s. what is their velocity aft
PIT_PIT [208]

Their velocity afterward is  v=3.467 m/s

Explanation:

Given:

Mass of the first football player= 91.5 kg

Initial velocity of the football player 3.73 m/s

Mass of second football player=63.56 kg

Initial velocity of the second football player=3.09 m/s

To find:

Final velocity of both players=?

Solution:

According to the law of conservation of momentum,

Initial momentum =final momentum

mathematically represented as  

m_1u_1+m_2u_2=m_1v_1+m_2v_2...........................(1)

where

u_1=intial velocity of the football player

u_2 = inital velocity of second football player

v_1=finall velocity of the  first football player

v_2=final velocity of second football player

after tackling , both the football players moves with the same velocity,

so v_1=v_2=v

Hence equation (1) becomes

m_1u_1+m_2u_2=(m_1+m_2)v

v=\frac{m_1u_1+m_2u_2}{(m_1+m_2)}

now substituting the values,

v=\frac{(91.5\times+3.73)+(63.5\times3.09)}{(91.5+63.5)}v=\frac{(341.29+196.210)}{155}

v=\frac{537.5}{155}

v=3.467 m/s

7 0
3 years ago
How codominant inheritance patterns differ from dominant/recessive inheritance patterns
alekssr [168]
Its simple dominant and recessive inheritance patterns and organism would need two recessive alleles(rr) for the trait to be expressed but only one dominant allele for that trait to be expressed (RR or Rr) however in the case of co-dominant alleles the heterozygous state (Rr) would produce a third phenotype rather that the dominant phenotype.
3 0
3 years ago
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