Planck's Constant Determination - Revision history

Ist12916 at 09:59, 9 September 2022

2022-09-09T09:59:09Z

Ist165721 at 14:24, 21 April 2013

2013-04-21T14:24:44Z

Ist165721 at 13:31, 21 April 2013

2013-04-21T13:31:33Z

Ist165721: /* Protocol */

2013-04-21T13:02:27Z

Protocol

Ist165721 at 11:39, 21 April 2013

2013-04-21T11:39:50Z

Ist165721: moved Plank's Constant Determination to Planck's Constant Determination

2013-04-21T11:33:54Z

moved Plank's Constant Determination to Planck's Constant Determination

Ist165721: Continuação do texto

2012-05-30T08:07:45Z

Continuação do texto

Ist165721: Mais texto (títulos)

2012-05-27T20:37:05Z

Mais texto (títulos)

Ist165721: Texto inicial (incompleto)

2012-05-26T21:22:02Z

Texto inicial (incompleto)

New page

=Description of the Experiment=
The purpose of this experiment is to study the photoelectric effect in metal and the determination of Plank's constant, since the former is of a quantic nature.

The light created by a mercury bulb is passed through a diffraction net to separate its spectral lines (i.e., the colours of the spectrum, just as a rainbow is a separation of the sunlight) and is used to force the emission of electrons in a photoelectric cell for each colour.

=Experimental Apparatus=
Under construction.

=Protocol=
There are two steps to achieve the goals of this experiment:

# Identify the angle for which the spectral lines are visible;
# Select the line to analyse and the filters to avoid reflected light with different wavelenghts.

To identify the lines, the experiment must first be done in sweep mode. This way, the output of phototransistor will show what are the angles that have light. The order of the peaks is shown in table 1

[[File:Plank-graph.png|thumb|alt=Graph with the phototransistor's output where the angles for the spectral lines can be identified.|Figure 1: Graph with the phototransistor's output.]]

{| border="1" style="text-align: center;"
|+ Table 1 – Caracteristic wavelengths for the mercuty lamp
|-
!Colour
!Frequency (Hz)
!Approximate wavelength (nm)
|-
|Violeta longínquo
|8.22x1014
|365
|-
|Violeta
|7.41x1014
|405
|-
|Azul
|6.88x1014
|436
|-
|Verde
|5.49x1014
|546
|-
|Amarelo
|5.19x1014
|578
|}

Obs:
# The experiment will automatically turn the mercury bulb off after 30min. After this happens, there is a 15min waiting period to stabilize the power running through the bulb.
# It is important to use the correct filter to avoid the superposition of two colours in the photocell, something that can occur because of diffusion of light.

@@ Line 1: / Line 1: @@
 =Description of the Experiment=
 The purpose of this experiment is to study the photoelectric effect in metal and the determination of Planck's constant, since the former is of a quantic nature.
@@ Line 16: / Line 17: @@
 </div>
 </div>
--->
@@ Line 139: / Line 140: @@
 =Links=
 *[[Determinação da Constante de Planck | Portuguese version (Versão em Português)]]

@@ Line 17: / Line 17: @@
 </div>
 -->
 =Experimental Apparatus=
 [[File:Espectro_dos_leds.png|thumb|alt=Led spectrum|Figure 1: Led spectrum.]]
-The photoelectric cell is a PASCO AP-9368, capacitor type cell, where one of the plates emits photoelectrons. These are stored in the other plate, which creates an electric potential between plates (and consequently, between the photocell's terminals). This potential increases with time until a maximum is reached. At this point, the capacitor stops charging (the potential energy).
+The photoelectric cell is a PASCO AP-9368, capacitor type cell, where one of the plates emits photoelectrons. These are stored in the other plate, which creates an electric potential between plates (and consequently, between the photocell's terminals). This potential increases with time until a maximum is reached. At this point, the capacitor stops charging (the potential energy is greater than the photoelectron's kinetic energy). For each wavelength, the electric potential will be different.

← Older revision		Revision as of 11:39, 21 April 2013
Line 82:		Line 82:
	=Historical Elements=		=Historical Elements=
	In 1921, Albert Einstein won the Nobel Physics Prize for his discovery of the law of photoelectric effect.		In 1921, Albert Einstein won the Nobel Physics Prize for his discovery of the law of photoelectric effect.
		+
		+
		+	=Links=
		+	*[[Determinação da Constante de Planck \| Portuguese version (Versão em Português)]]

@@ Line 21: / Line 21: @@
 {| border="1" style="text-align: center;"
-|+ Table 1 – Caracteristic wavelengths for the mercuty lamp
+|+ Table 1 – Caracteristic wavelengths for the mercury lamp
 |-
 !Colour
@@ Line 54: / Line 54: @@
 ==Plank's Constant Determination==
-Under construction.
-<!--
-By running the experiment in NORMAL mode, the output will be the time caracteristic of the capacitor's charge,
+UNDER CONSTRUCTION.
--->
+By running the experiment in NORMAL mode, the output will be a time-dependent graph of the capacitor's charge, which is determined by the current created by the photocell. The less time is takes to charge the cpacitor, the higher the current will be, which means higher light intensity (as shown in the advanced prtocol).
 =Advanced Protocol=

← Older revision		Revision as of 20:37, 27 May 2012
Line 51:		Line 51:
	# The experiment will automatically turn the mercury bulb off after 30min. After this happens, there is a 15min waiting period to stabilize the power running through the bulb.		# The experiment will automatically turn the mercury bulb off after 30min. After this happens, there is a 15min waiting period to stabilize the power running through the bulb.
	# It is important to use the correct filter to avoid the superposition of two colours in the photocell, something that can occur because of diffusion of light.		# It is important to use the correct filter to avoid the superposition of two colours in the photocell, something that can occur because of diffusion of light.
		+
		+
		+	==Plank's Constant Determination==
		+	Under construction.
		+	<!--
		+	By running the experiment in NORMAL mode, the output will be the time caracteristic of the capacitor's charge,
		+	-->
		+
		+	=Advanced Protocol=
		+	Under construction.
		+
		+
		+	==Classic model for radiation and particle model==
		+	Under construction.
		+
		+
		+	=Theoretical Principles=
		+	Under construction.
		+
		+
		+	==Photoelectric Effect==
		+	Under construction.
		+
		+
		+	=Historical Elements=
		+	In 1921, Albert Einstein won the Nobel Physics Prize for his discovery of the law of photoelectric effect.

@@ Line 27: / Line 27: @@
 !Approximate wavelength (nm)
 |-
-|Violeta longínquo
+|Ultra violet
 |8.22x1014
 |365
 |-
-|Violeta
+|Violet
 |7.41x1014
 |405
 |-
-|Azul
+|Blue
 |6.88x1014
 |436
 |-
-|Verde
+|Green
 |5.49x1014
 |546
 |-
-|Amarelo
+|Yellow
 |5.19x1014
 |578
@@ Line 62: / Line 62: @@
 UNDER CONSTRUCTION.
 =Advanced Protocol=

← Older revision	Revision as of 11:33, 21 April 2013
(No difference)