1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
svet-max [94.6K]
3 years ago
12

Microwave ovens use microwave radiation to heat food. the microwaves are absorbed by the water molecules in the food, which is t

ransferred to other components of the food. as the water becomes hotter, so does the food. part a suppose that the microwave radiation has a wavelength of 11.2 cm . how many photons are required to heat 225 ml of coffee from 25.0 ∘c to 62.0 ∘c? assume that the coffee has the same density, 0.997 g/ml , and specific heat capacity, 4.184 j/(g⋅k) , as water over this temperature range.
Physics
2 answers:
PIT_PIT [208]3 years ago
7 0
<span>step 1: energy required to heat coffee E = m Cp dT E = energy to heat coffee m = mass coffee = 225 mL x (0.997 g / mL) = 224g Cp = heat capacity of coffee = 4.184 J / gK dT = change in temp of coffee = 62.0 - 25.0 C = 37.0 C E = (224 g) x (4.184 J / gK) x (37.0 C) = 3.46x10^4 J step2: find energy of a single photon of the radiation E = hc / λ E = energy of the photon h = planck's constant = 6.626x10^-34 J s c = speed of light = 3.00x10^8 m/s λ = wavelength = 11.2 cm = 11.2 cm x (1m / 100 cm) = 0.112 m E = (6.626x10^-34 J s) x (3.00x10^8 m/s) / (0.112 m) = 1.77x10^-16 J step3: Number of photons 3.46x10^4 J x ( 1 photon / 1.77x10^-16 J) = 1.95x10^20 photons</span>
mafiozo [28]3 years ago
4 0

Answer:

n = 1.96 \times 10^{28} photons

Explanation:

Mass of the coffee is given as

mass = density\times volume

here we know that

density = 0.997 g/ml

volume = 225 ml

now mass of coffee will be

m = 0.997 \times 225 = 224.325 g

now heat required to raise the temperature of coffee will be

Q = ms\Delta T

Q = 224.325 \times 4.184 \times (62 - 25)

Q = 34727.3 J

now we know that energy of one photon is

E = \frac{hc}{\lambda}

E = \frac{(6.6 \times 10^{-34}) ( 3 \times 10^8)}{0.112}

E = 1.77 \times 10^{-24} J

now it requires "n" photons to complete the energy

n\times (1.77 \times 10^{-24}) = 34727.3

n = 1.96 \times 10^{28}

You might be interested in
A 60.0-kg skater begins a spin with an angular speed of 6.0 rad/s. By changing the position of her arms, the skater decreases he
juin [17]

The skater's final angular speed is equal to 12 rad/s.

When implemented to angular momentum, the regulation of conservation means that the momentum of a rotating item is no longer exchanged until some form of external torque is carried out. Torque, in this sense, can check with any outside pressure that acts upon the object for the purpose to twist or rotate.

The law of conservation of angular momentum states that once no external torque acts on an item, no trade of angular momentum will occur. The angular momentum of a machine is conserved as long as there may be no net external torque performing on the machine.

In angular kinematics, the conservation of angular momentum refers back to the tendency of a device to keep its rotational momentum inside the absence of outside torque. For a round orbit, the system for angular momentum is (mass) ×(pace) ×(radius of the circle): (angular momentum) = m × v × r.

Learn more about angular momentum here brainly.com/question/7538238

#SPJ4

7 0
2 years ago
A bat strikes a 0.145-kg baseball. Just before impact, the ball is traveling horizontally to the right at 60.0 m/s , and it leav
nata0808 [166]

Answer:

F = -307.4 N

Explanation:

It is given that,

Mass of the baseball, m = 0.145 kg

Initial speed of the baseball, u = 60 m/s

Final speed of the baseball, v=65\ cos(30)=56.29\ m/s

Time of contact, t=1.75\ ms=1.75\times 10^{-3}\ s

(a) It is assumed to find the horizontal component of average force. It is given by :

F=m\dfrac{v-u}{t}

F=0.145\dfrac{56.29-60}{1.75\times 10^{-3}}

F = -307.4 N

So, the horizontal component of average force is 307.4 N. Hence, this is the required solution.

8 0
3 years ago
. Two identical vehicles traveling at the same speed are made to collide with barriers in an insurance company collision test. T
Serggg [28]

Answer:

F₁ / F₂ = 10

therefore the first out is 10 times greater than the second barrier

Explanation:

For this exercise let's use the relationship between momentum and momentum.

         I = F t = Δp

in this case the final velocity is zero

        F t = 0 -m v₀

        F = m v₀ / t

in order to answer the question we must assume that the two vehicles have the same mass and speed

concrete barrier

        F₁ = -p₀ / 0.1

        F₁ = - 10 p₀

barrier collapses

         F₂ = -p₀ / 1

let's look for the relationship of the forces

        F₁ / F₂ = 10

therefore the first out is 10 times greater than the second barrier

5 0
3 years ago
Using the set-up seen here, Ms. Garcia places a golf ball between the globe and the flashlight. Turning off the lights in the ro
Julli [10]
This is a solar Eclipse.  
7 0
3 years ago
A certain white dwarf star was once an average star like our Sun. But now it is in the last stage of its evolution and is the si
solmaris [256]

Answer:

4.384 * 10^13

Explanation:

Given the expression :

[(6.67 * 10^-11) * (1.99 * 10^30)] ÷ [(1.74*10^3)*(1.74*10^3)]

Applying the laws of indices

[(6.67 * 1.99) *10^(-11 + 30)] ÷ [(1.74 * 1.74) * 10^3+3]

13.2733 * 10^19 ÷ 3.0276 * 10^6

(13.2733 / 3.0276) * 10^(19 - 6)

4.3840996 * 10^13

= 4.384 * 10^13

6 0
3 years ago
Other questions:
  • You compress a spring by a certain distance. then you decide to compress it further so that its elastic potential energy increas
    11·1 answer
  • Which of the following describes what needs to occur to reduce force and to do the same amount of work?
    14·1 answer
  • A circuit contains three light bulbs in parallel. After observation, a fourth light bulb is added, also in parallel. How does th
    6·2 answers
  • Based on the law of conservation of energy, how can we reasonably improve a machine’s ability to do work?
    13·2 answers
  • You throw a rock straight up and find that it returns to your hand 3.40 s after it left your hand. Neglect air resistance. What
    14·1 answer
  • How would you find the speed of a person who walked
    12·1 answer
  • The sum of the interior angles of a quadrilateral is _______. 180° 90° 270° 360°
    14·2 answers
  • Answer all of these questions and you will get the brainlist
    14·1 answer
  • to what temperature it will a 30 KG of glass raise if it absorbs 4275 joules of heat in its specific heat is 0.5 J/KG degree cel
    9·1 answer
  • Momentum of an object is determined to be 7.2 ×10 to the negative 3 kg
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!