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
Oduvanchick [21]
2 years ago
14

What does the blackboard do when white light falls on it?​

Physics
1 answer:
shusha [124]2 years ago
5 0
Actually a black board has all colours in light or white light . So when light falls on it board absorbs all colours because all are present so no light is reflected back. That is the case, and so it will appear black as it absorbs all colours of light that fall on it .
You might be interested in
In which situation is the maximum possible work done? A. when the angle between the force and displacement is 0° B. when the ang
Flauer [41]

Answer:

C

Explanation:

7 0
3 years ago
Read 2 more answers
Someone got this paper?
Snezhnost [94]
First question (upper left):
1/Req = 1/12 + 1/24 = 1/8
Req = 8 ohms
Voltage is equal through different resistors, and V1 = V2 = 24 V.
Current varies through parallel resistors: I1 = V1/R1 = 24/12 = 2 A. I2 = 24/24 = 1 A.

Second question (middle left):
V1 = V2 = 6 V (parallel circuits)
I1 = 2 A, I2 = 1 A, IT = 2+1 = 3 A.
R1 = V1/I1 = 6/2 = 3 ohms, R2 = 6/1 = 6 ohms, 1/Req = 1/2 + 1/1, Req = 2/3 ohms

Third question (bottom left):
V1 = V2 = 12 V
IT = 3 A, meaning Req = V/It = 12 V/3 A = 4 ohms
1/Req = 1/R1 + 1/R2, 1/4 = 1/12 + 1/R2, R2 = 6 ohms
I1 = V/R1 = 1 A, I2 = V/R2 = 2 A

Fourth question (top right):
1/Req = 1/20 + 1/20, Req = 10 ohms
IT = 4 A, so VT = IT(Req) = 4*10 = 40 V
Parallel circuits, so V1 = V2 = VT = 40 V
Since the resistors are identical, the current is split evenly between both: I1 = I2 = IT/2 = 2 A.

Fifth question (middle right):
1/Req = 1/5 + 1/20 + 1/4, Req = 2 ohms
IT = VT/Req = 40 V/2 ohms = 20 A
V1 = V2 = V3 = 40 V
The current of 20 A will be divided proportionally according to the resistances of 5, 20, and 4, the factors will be 5/(5+20+4), 20/(5+20+4), and 4/(5+20+4), which are 5/29, 20/29, and 4/29.
I1 = 20(5/29) = 100/29 A
I2 = 20(20/29) = 400/29 A
I3 = 20(4/29) = 80/29 A

Sixth question (bottom right):
V2 = 30V is given, but since these are parallel circuits, V1 = VT = 30 V.
Then I1 = V1/R1 = 30 V/10 ohms = 3 A.
I2 = 30 V/15 ohms = 2 A.
IT = 3 + 2 = 5 A
1/Req = 1/10 + 1/15, Req = 6 ohms
6 0
3 years ago
A crane used 250,000 Joules of work to move a beam to the top of a building in 20 seconds. How much power did the crane use?
maria [59]

Answer:

12500W

Explanation:

Given parameters:

Work done  = 250000J

Time taken  = 20s

Unknown:

Power of the crane = ?

Solution:

Power is the defined as the rate at which work is being done;

  Mathematically;

        Power = \frac{work done}{time }

 insert the parameters and solve;

      Power  = \frac{250000}{20}   = 12500W

7 0
3 years ago
6. (a) Suppose the earth is revolving round the sun in a circular orbit of radius one b astronomical unit (1.5% 10 km). Find the
kkurt [141]

Answer:

tough

ques

Explanation:

5 0
2 years ago
__________ and __________ both agreed that childhood experiences play an important role in the development of oneself.
oksano4ka [1.4K]
The following answers in the blank could be Sigmund Freud who found the psychoanalysis and Karen Horney who is known to be a psychoanalyst. Both of them has the idea that childhood experiences is necessary and plays the important role in the individual as he or she grows.
8 0
3 years ago
Read 2 more answers
Other questions:
  • Problem 6.056 Air enters a compressor operating at steady state at 15 lbf/in.2, 80°F and exits at 275°F. Stray heat transfer and
    7·1 answer
  • What happens to the electronegativity of elements as you move from bottom left to upper right across the periodic table?
    13·1 answer
  • After landing on an unfamiliar planet, a space explorer constructs a simple pendulum of length 55.0 cm. She finds the pendulum m
    12·1 answer
  • What is a cool example of newtons 3rd law?
    12·2 answers
  • A brass rod 175.00 mm long and 5.00 mm in diameter extends horizontally from a casting at 200°C. The rod is in an air environmen
    5·1 answer
  • An oscillator makes 360 vibrations in 3 minutes.
    6·2 answers
  • How can I describe an Electric Current?
    10·1 answer
  • A 10,000 N piano is dropped from the top of a building. When the piano reaches terminal speed…
    6·1 answer
  • Howkim has two magnetic first he put gthem beside
    9·1 answer
  • Need thy help once again
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!