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3 years ago

Who was the first to state the concept of an atom?

2 answers:

4 0

Democritus was the first to state the concept of an atom; he proposed that matter is made up of tiny, indivisible particles called atoms

Naddik [55]3 years ago

3 0

Answer:

Democritus

Explanation:

Greek philosophers Leucippus and Democritus first developed the concept of the atom in the 5th century BC

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If you double the voltage in a circuit and reduce the resistance by a factor of four what will happen to the current? A) it will

KatRina [158]

By Ohm's Law, we can relate current, voltage and resistance. It is expressed as V=IR. That is, there is a direct relationship between voltage and resistance and voltage and current.

V = IR
V1/2V1 = I1R1 / I2R1/4
1/2 = 4I1/I2
I2 = 8I1

Therefore, <span> it will increase by a factor of 8. Hope this answers the question.</span>

5 0

3 years ago

To what tension (in newtons) must you adjust the screw so that a transverse wave of wavelength 3.33 cm makes 621 vibrations per

PilotLPTM [1.2K]

Answer:

T=9.4 N

Explanation:

We are given that

Mass of wire,m=16.5 g= $\frac{16.5}{1000}$ kg

1 kg=1000g

Length of wire,l=75 cm= $75\times 10^{-2}$ m

1 m=100 cm

Wavelength of transverse wave= $\lambda=3.33 cm=3.33\times 10^{-2}$ m

Frequency= $621 Hz$

Mass per unit length= $m_l=\frac{m}{l}=\frac{16.5}{1000\times 75\times 10^{-2}}=0.022 kg/m$

$\nu=\frac{v}{\lambda}$

$v=\nu \lambda$

Where $\nu=$ frequency of wave

$\lambda$ =Wavelength of wave

Speed of wave=v

Using the formula

$v=3.33\times 10^{-2}\times 621=20.7m/s$

$v=\sqrt{\frac{T}{m_l}}$

$v^2=\frac{T}{m_l}$

$T=v^2m_l$

Using the formula

$T=(20.7)^2\times 0.022=9.4N$

Hence, the tension,T=9.4 N

7 0

3 years ago

How many photons per second are emitted by a monochromatic lightbulb (650 nm) that emits 45 W of power? Express your answer usin

Fudgin [204]

Answer:

The number of photons per second are $7.95\times10^{11}\ photons/s$ .

Explanation:

Given that,

Wavelength = 650 nm

Power = 45 W

Distance R= 17 m

Diameter = 5.0 mm

We need to calculate the number of photon per second emitted by light bulb

Using formula of energy

$E=\dfrac{hc}{\lambda}$

The power is

$P=\dfrac{nE}{t}$

$\dfrac{n}{t}=\dfrac{P}{E}$

Put the value of E

$\dfrac{n}{t}=\dfrc{P \lambda}{hc}$

Put the value into the formula

$\dfrac{n}{t}=\dfrac{45\times650\times10^{-9}}{6.6\times10^{-34}\times3\times10^{8}}$

$\dfrac{n}{t}=1.47\times10^{20}\ photons/s$

We need to calculate the surface area

Using formula of area

$A=4\piR^2$

$A=4\pi\times17^2$

We need to calculate the number of photons entering into eye

$N=n\dfrac{A_{eye}}{A_{surface}}$

$N=1.47\times10^{20}\times\dfrac{\pi(2.5\times10^{-3})^2}{4\pi\times17^2}$

$N=7.95\times10^{11}\ photons/s$

Hence, The number of photons per second are $7.95\times10^{11}\ photons/s$ .

4 0

3 years ago

Read 2 more answers

In an evironmental system of subsystem, the mass balance equation is:__________.

kolbaska11 [484]

Answer:

Explanation:

The mass balance is an application of conservation of mass, to the analysis of physical system. This is given in an equation form as

Input = Output + Accumulation

The conservation law that is used in this analysis of the system actually depends on the context of the problem. Nevertheless, they all revolve around conservation of mass. By conservation of mass, I mean that the fact that matter cannot disappear or be created spontaneously.

8 0

3 years ago

haun wants to enter the science fair at his school. he has a list of ideas for his project. which questions could be answered th

Allisa [31]

Correct Answer:

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- Which brand of soap is the best for cleaning grease off dishes?

6 0

2 years ago