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Kinematics
Dynamics
Statics
Energy conservation laws in mechanics
Fluid and gas pressure
Molecular kinetics
Heat (thermal) phenomenons
Vapor, fluid (liquids), solid state
Thermodynamics
Electrostatics
Continuous (direct) current
Magnetic field
Electromagnetic induction
Electric current in metals
Mechanical oscillations
Mechanical waves
Electromagnetic oscillations
Alternating current
Electromagnetic waves
Photometry
Geometrical (ray) optics
Wave optics
Quantum optics
Relativity theory
Atom and nucleus of atom

Physics formulas
Photometry
Illuminance (illuminancy)

Illuminance (illuminancy)

$E = \frac{I}{R^{2}}$

E - illuminance
I - light intensity
R - distance

Find

E
I
R

It is known that:

=

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1
a
A
δ
Δ

1

2

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+

<-

4

5

6

-

C

7

8

9

*

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√

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log

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arc cos

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a

b

c

d

e

f

g

h

i

j

k

l

m

n

o

p

q

r

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t

u

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x

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z

A

C

P

A

B

C

D

E

F

G

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I

J

K

L

M

N

O

P

Q

R

S

T

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α

β

γ

δ

ε

ζ

η

θ

ι

κ

λ

μ

ν

ξ

ο

π

ρ

σ

τ

υ

φ

χ

ψ

ω

ß

ℏ

Α

Β

Γ

Δ

Ε

Ζ

Η

Θ

Ι

Κ

Λ

Μ

Ν

Ξ

Ο

Ρ

Σ

Τ

Υ

Φ

Χ

Ψ

Ω

Ā