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
dybincka [34]
3 years ago
8

RACTIC PTUDIES

Physics
1 answer:
Amanda [17]3 years ago
6 0

Answer:

The illumination on the book before the lamp is moved is 9 times the illumination after the lamp is moved.

Explanation:

The distance of the book before the lamp is moved, d_{b} = 30 cm

The distance of the book after the lamp is moved, d_{a} = 90 cm

Illumination can be given by the formula, E = \frac{P}{4 \pi d^{2} }

Illumination before the lamp is moved, E_{b} = \frac{P}{4 \pi d_{b} ^{2} }

Illumination after the lamp is moved, E_{a} = \frac{P}{4 \pi d_{a} ^{2} }

\frac{E_{a}}{E_{b}} } = \frac{\frac{P}{4 \pi d_{a} ^{2} } }{\frac{P}{4 \pi d_{b} ^{2} } }

\frac{E_{a} }{E_{b} } = \frac{d_{b} ^{2} }{d_{a} ^{2}} \\\frac{E_{a} }{E_{b} } = \frac{30^{2} }{90 ^{2}}\\\frac{E_{a} }{E_{b} } =\frac{900 }{8100}\\\frac{E_{a} }{E_{b} } =\frac{1 }{9}

E_{b} = 9E_{a}

The illumination on the book before the lamp is moved is 9 times the illumination after the lamp is moved.

You might be interested in
What is the electric field strength at a distance of .50 m from a 1.00x10^-6 c charge?
ss7ja [257]

Answer:

e = k q / r² then,

e = 9×10^9 * 1×10^-6 / 50² = 3.6 N/C

hope this helps ❤.

7 0
2 years ago
Who pioneered the use of galvanoplastic compounds for preserving footprints and ballistics?
alukav5142 [94]

Answer:

Option D (Alphonse Bertillon) is the correct response.

Explanation:

  • He seems to have been a policeman turned biometrics expert from France. Forensic techniques such as forensic record analysis were developed by Bertillon.
  • To retain proof, he always pioneered or developed the use of such galvanoplastic compounds as molds for footsteps as well as ballistics. To research physical changes with age, Bertillon has developed a method focused on images of almost the same person’s performance.

All those other choices weren’t connected to the instance offered. So, the best one is the one described.

5 0
3 years ago
Read 2 more answers
What is an isotope ?
Step2247 [10]

<span>An isotope is a form of a chemical element whose atomic nucleus contains a specific number of neutrons in addition to the number of protons that distinctively defines the element. The nuclei of most atoms have neutrons as well as protons.</span>

8 0
3 years ago
Which wind blows cool air inland during the day?<br><br> global winds<br> land breeze<br> sea breeze
Tasya [4]

Answer:

global winds A

Explanation:

3 0
3 years ago
Read 2 more answers
Currents circulate in a piece of metal that is pulled through a magnetic field. What are these currents called?
MariettaO [177]
<h3><u>Answer;</u></h3>

Eddy currents

<h3><u>Explanation</u>;</h3>
  • <em><u>Eddy currents are currents which circulate in conductors like swirling eddies in a stream. These currents are induced by changing magnetic fields and flow in closed loops, perpendicular to the plane of the magnetic field. </u></em>
  • They are created as a result of change in the intensity or direction of a magnetic field on a conductor, this occurs either when a conductor is moving through a magnetic field, or when the magnetic field surrounding a stationary conductor is varying
4 0
3 years ago
Other questions:
  • What is true about isolines on a weather map?
    8·2 answers
  • What happens when a electron and a proton get close together?
    15·1 answer
  • What type of energy is the energy of motion?
    11·2 answers
  • How can the distance between the first bright band and the central band be increased in a double-slit experiment?
    8·1 answer
  • a motorcycle is trying to leap across the canyon by driving horizontally off a cliff 38 m/s. Ignoring air resistance, find the s
    11·1 answer
  • Write the electric field at point p in component form. assume that x-axis is horizontal and points to the right, and y-axis poin
    6·1 answer
  • What is Darwin's theory of the origin of species?
    9·1 answer
  • A 2.0 x 10^3 kilogram car collides with a tree and is brought to
    12·1 answer
  • When an unbalanced force acts on an object
    7·1 answer
  • A weather forecast for a certain day in an area shows two measurements, 18 degrees Celsius and 25 degrees Celsius. What do these
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!