PLANCK’ CONSTANT - Birla Institute of Technology and...
Transcript of PLANCK’ CONSTANT - Birla Institute of Technology and...
PLANCK’ CONSTANT
READ THE WARNING ON THE NEXT SLIDE BEFORE
STARTING THE EXPERIMENT
OPEN AC MAINS CONNECTIONS!
RED ALERT
● THIS EXPERIMENT INVOLVES OPEN AC VOLTAGE CONNECTIONS
● FIRST SWITCH OFF ALL THE AC MAINS CONNECTIONS; THEN MAKE THE CIRCUIT;
● DON’T EVEN ACCIDENTALLY TOUCH THE OPEN CONNECTIONS WHEN SWITCHED ON
APPARATUS USED IN THE PLANCK’S CONSTANT DETERMINATION EXPERIMENT
VARIAC
PHOTODIODE BOX WITH FILTERS
AC AMMETER
Battery eliminator
AC AND DC MILLIAMMETER (ONLY THE DC RANGES ARE USED)
VARIAC PLUG WHICH SHOULD BE REMOVED (SWITCH OFF FIRST) BEFORE MAKING THE CIRCUIT
PHOTODIODE BOX
A TUNGSTUN FILLAMENT BULB CONNECTED TO THE VARIAC
PHOTODIODE
FILTER IN FRONT OF THE OPENING
CHANGING THE FILTERS
WHEN YOU SEE
RED ON THE TOP
THE RED FILTER IS
ACTUALLY
VERTICALLY
BELOW IT AND
INFRONT OF THE
PHOTODIODE
HOW TO OPERATE THE VARIAC
A VARIAC TAKES IN AC MAINS AND GIVES OUT A VARIABLE VOLTAGE AC.
TAKE CARE NOT TO TOUCH THE OPEN WIRES/POINTS FROM THE VARIACSWITCH OFF AC MAINS FIRST; REMOVE THE PLUG; MAKE THE CIRCUIT CONNECTIONS; PLUG IN THE VARIAC AND SWITCH IT ON
THE VARIAC IS CONNECTED TO AC MAINS AND THE OUTPUT IS CONNECTED TO THE BULB AS SHOW LATER ON
TURN THE KNOB TO THE DESIRED OUTPUT VOLTAGE
`
THE NUMBER AGAINST THE POINTER REPRESENTS THE MAXIMIM DEFLECTION CURRENT IN MILLIAMPERES; IF THIS IS 1 mA AS SHOWN THEN IT IS CONVENIENT TO USE THE OUTER SCALE WHICH HAS 100 DIVISIONS.
HOW TO USE THE AMMETER: USE THE LEFT SIDE FOR DC MILLIAMPERES
THIS METER IS USED TO KNOW THE
CURRENT THROUGH THE PHOTODIODE
THE METER IS
SHOWING 60 ON
THE SCALE OF 100
AND THE RANGE
SELECTION KNOB
WAS POINTING AT 1
mA so the current
flowing is 0.6 mA.
FOR THE SAME CURRENT IF WE CHOOSE THE
RANGE AS 3 mA THEN IT IS CONVENIENT TO
READ FROM THE LOWER SCALE ON THE DIAL:
SINCE FULL SCALE DIFLECTION SHOULD BE 3
mA (which corresponds to 30 divisions) 6 DIVISIONS
CORRESPOND TO 0.6 mA
AS BEFORE
TWO CIRCUITS
PALE RED AND THE BLACK ARE THE WIRES FROM THE BULB; THESE ARE CONNECTED TO THE VARIAC VIA (yellow) AMMETER AS SHOWN
CIRCUIT ONE:THE BULB CIRCUITSWITCH OFF THE VARIAC; REMOVE ITS PLUG;
CONNECT ITS OUTPUT TO THE BULB WITH THE AC AMMETER IN SERIES AS SHOWN; THE VOLTAGE IS READ FROM THE VARIAC DIAL; CURRENT FROM THE AMMETER
ONLY WHEN YOU HAVE MADE THIS CIRCUIT PLUG IN THE VARIAC AND SWITCH IT ON; NOW DON’T TOUCH THE OPEN PART OF THIS CIRCUIT; TURN ONLY THE KNOB
BULB CIRCUIT AT A GLANCE; STEP BY STEP GIVEN LATER ON
CIRCUIT TWO: PHOTODIODE CONNECTION
THIS IS A LOW VOLTAGE DC
CONNECTION
THE BATTERY
ELIMINATOR IS
CONNECTED TO THE
PHOTODIODE WITH THE
AMMETER IN SERIES
PHOTODIODE CIRCUIT AT A GLANCE; STEP BY STEP GIVEN LATER ON
PROCEDURE
● AFTER MAKING THE CIRCUIT FOLLOW THE PROCEDURE GIVEN
IN THE MANUAL
● BRIEFLY: FOR A GIVEN FILTER VARY THE VOLTAGE NOTING
DOWN THE CURRENTS THROUGH THE BULB AND THROUGH
THE PHOTODIODE; DO THIS FOR THE THREE FILTERS
STEP BY STEP BULB CIRCUIT
THIS BEING AN AC CIRCUIT THE POLARITIES DON’T
MATTER; NOT MUCH TO WORRY WHETHER YOU TAKE
THE RED OR THE BLACK WIRE LEADING TO THE BULB;
FOR THE SAME REASON YOU WILL GET A SHOCK BY
TOUCHING ANY ONE IF THE CIRCUIT IS ON!
ONE OF THE WIRES (BLACK ) LEADING TO THE BULB IS CONNECTED TO ONE OF THE OUT PUT
POINTS OF THE VARIAC
IGNORE THE BLACK-WHITE WIRE IN THE BACKGROUND!
ANOTHER WIRE (YELLOW) CONNECTS THE OTHER POINT OF THE VARIAC TO ONE OF THE POINTS (BLACK) OF THE AC AMMETER
THE SECOND WIRE (RED) LEADING TO THE BULB IS CONNECTED TO THE REMAINING POINT (RED) OF THE AC AMMETER
THE PHOTODIODE CIRCUIT
THIS IS A DC CIRCUIT SO POLARITIES DO
MATTER. READ THE MANUAL CAREFULLY
BEFORE MAKING THE CONNECTIONS AS
SHOWN TO BE DOUBLY SURE. IF IN DOUBT
GET THE CIRCUIT CHECKED BEFORE
SWITCHING ON THE BATTERY ELIMINATOR
THE METER IS SHOW VERTICAL FOR CLARITY; YOU SHOULD KEEP IT HORIZONTAL ONLY; OTHERWISE ITS POINTER WILL BE DEFLECTED
UNDER ITS OWN WEIGHT
http://nobelprize.org/nobel_prizes/physics/laureates/1918/planck.html
Max Karl Ernst Ludwig Planck
Born: 23 April 1858, Kiel, Schleswig (now Germany)Died: 4 October 1947, Goettingen, West GermanyAffiliation at the time of the award: Berlin University, Berlin, GermanyPrize motivation: "in recognition of the services he rendered to the advancement of Physics by his discovery of energy quanta"Field: Quantum mechanicsMax Planck received his Nobel Prize one year later, in 1919.
WHAT IS A PLANCK LENGTH?
THIS QUESTION HAS NOTHING MUCH TO DO WITH
THIS EXPERIMENT AND THERE IS NO FEAR THAT
YOU MAY BE ASKED THIS IN THE VIVA OR THE
COMPRE;
BUT
THERE IS A LIFE BEYOND GRADING!