All categories

2 years ago

9. How much energy does a 100 W light bulb use in half an hour? If the light bulb converts

1 answer:

6 0

The energy used by the light bulb in half an hour is 180000 J and the amount of thermal energy generated is 158400 J.

What is Energy?

Energy is the ability or the capacity to do work.

To calculate the energy of the light bulb we use the formula below

Formula:

E = Pt.......... Equation 1

Where:

E = Energy used by the bulb in a half-hour
P = Power of the bulb
t = Time

Given:

P = 100 W
t = 1/2 hour = 30 minutes = (30×60) = 1800 seconds

Substitute these values into equation 1

E = (100×1800)
E = 180000 J

If the light converts 12% of electric energy to light energy, then 88% of the energy is used to generate thermal energy

Therefore,

Thermal energy = (180000×88/100) = 158400 J

Hence, the energy used by the light bulb in half an hour is 180000 J and the amount of thermal energy generated is 158400 J.

Learn more about energy here: brainly.com/question/21927255

#SPJ1

You might be interested in

A ball is launched upward at an angle from the ground. Which way does its velocity point at the top?

gogolik [260]

The answer is B because at the very top the acceleration is ZERO so it isn’t moving

7 0

3 years ago

A wave has wavelength of 8m and a speed of 360 m/s. What is the frequency of the wave?

Naily [24]

Answer:

$45~ \text{Hz}.$

Explanation:

$\text{Frequency,}~ f = \dfrac{v}{\lambda}\\\\\\~~~~~~~~~~~~~~~~~~=\dfrac{360~ \text{ms}^{-1}}{8~ \text m}\\\\\\~~~~~~~~~~~~~~~~~~=45~ \text s^{-1}\\\\\\~~~~~~~~~~~~~~~~~~~=45~ \text{Hz}$

8 0

2 years ago

A projectile is launched from ground level at angle u and speed v0 into a headwind that causes a constant horizontal acceleratio

ale4655 [162]

Answer:

Explanation:

Given

Launch angle =u

Initial Speed is $v_0$

Horizontal acceleration is $a_x=a$

At maximum height velocity is zero therefore

$v_f=v_i-gt$

$0=v_0\sin u-gt$

$t=\frac{v_0\sin u}{g}$

Total time of flight $T=2t=\frac{2v_0\sin u}{g}$

During this time horizontal range is

$R=v_o\cos u\cdot 2t-\frac{a(2t)^2}{2}$

$R=\frac{2v_0^2\sin u\cos u}{g}-\frac{2av_0^2\sin ^u}{g^2}$

For maximum range $\frac{\mathrm{d} R}{\mathrm{d} u}=0$

$\frac{\mathrm{d} R}{\mathrm{d} u}=\frac{2v_0^2\cos 2u}{g}-\frac{4av_0^2\sin u\cos u}{g^2}$

$\frac{\mathrm{d} R}{\mathrm{d} u}=\frac{2v_0^2}{g}\left [ \cos 2u-\frac{a}{g}\sin 2u\right ]=0$

$\tan 2u=\frac{g}{a}$

$u=\frac{1}{2}tan ^{-1}\frac{g}{a}$

(b)If a =10% g

$a=0.1g$

thus $u=\frac{1}{2}tan^{-1}\frac{g}{0.1g}$

$u=42.14^{\circ}$

7 0

3 years ago

A device that assures the delivery of electric power without interruption is a(n)?

mario62 [17]

The answer should be UPS

5 0

2 years ago

You have a rock sample and analyze it for the presence of radioactive isotopes in order to determine when it was formed. You fin

Firdavs [7]

Answer:

the decay of half of the nuclei only a half-life has passed , b) in rock time it is 1 108 years

Explanation:

The radioactive decay is given by

N = N₀ $e^{\lambda t}$

If half of the atoms have decayed

½ N₀ = N₀ $e^{\lambda t}$

½ = $e^{\lambda t}$ ₀

Ln 0.5 = - λ t

t = - ln 0.5 /λ

The definition of average life time is

$T_{1/2}$ = ln 2 / λ

λ = ln 2 / $T_{1/2}$

λ = 0.693 / 100 10⁶

λ = 0.693 10⁻⁸ years

We replace

t = -ln 0.5 / 0.693 10⁻⁸

t = 10⁸ years

We see that for the decay of half of the nuclei only a half-life has passed

b) in rock time it is 1 108 years

8 0

3 years ago