Physics: Post your doubts here!

[rami-mustang_gt]

PLEASE HELP ME
WHAT ARE THE CONDITIONS FOR DIFFRACTION GRATING ??

 

[rami-mustang_gt]

YOU HAVE SHORTED AND BROKEN LAMPS.
WHEN THERE IS A BREAK IN THE FILAMENT OF THE LAMP, R=INFINITE ohms
WHEN THE FILAMENT MELTS DOWN TO GIVE THICK SHORT WIRE R=0 ohms

 

[confused123]

th

Switch closed means the power pass through that part of circuit(through the closed switch) and as the heating elements are similar they all have the same constant resistance. So calculate the parallel resistances and thereby calculate the TOTAL RESISTANCE of the heating elements in circuit where the current passes. The calculate the power using the total resistance. The power supply is providing a constant emf of 240v. Contact me for more details.

thanks a lot man, but can you write a reason for every calculation in the table.

 

[confused123]

PLEASE HELP ME
WHAT ARE THE CONDITIONS FOR DIFFRACTION GRATING ??

please turn of the caps lock!

in order to observe diffraction, width of the opening or gap should be comparable with the wavelength of waves passing through.

 

[anonymous123]

Hey Guys and Gals.... Need a last minute revision notes for AS physics... Check these out...Want more??? Then like me and just ask...Im kinda busy these days..but ill try my best to provide more notes

Unit 1-Quantities and their Measurements​

Unit 2-Motion,Force and Energy​

Unit 3-Electric charge​

Unit 4-Matter​

Unit 4-Atomic physics​

Unit 5-Waves​

more

 

[raamish]

Wow the notes are awsum more please )

 

[raamish]

http://www.xtremepapers.com/papers/...and AS Level/Physics (9702)/9702_s08_qp_2.pdf

Qs 6b iv) The circuit will become series when switch s1 and s2 are closed. But im using this formula V=IR to calculate the current which is coming 6.25A. then im using the formula P=I2R to calculate the power. These are the values i put: P=6.25*6.25*(38.4+38.4). But my answer is coming wrong. What am i doing wrong please help me

 

[dilchan]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s08_qp_2.pdf

Qs 6b iv) The circuit will become series when switch s1 and s2 are closed. But im using this formula V=IR to calculate the current which is coming 6.25A. then im using the formula P=I2R to calculate the power. These are the values i put: P=6.25*6.25*(38.4+38.4). But my answer is coming wrong. What am i doing wrong please help me

In this case A and B are parallel. Then Current through each is 6.25A. The P=(P in A)+(P in B)=(6.25*240)+(6.25*240)=3000w... Easy way is to find combined resistance of A and B and use P=(V*V)/R...where R is the combined resistance of the two parallel resistors A and B....... R=(38.4*38.4)/(38.4+38.4)=19.2 ohms... Now use P=(V*V)/R=(240*240)/19.2=3000W. Even i am doubtful, but the correct answer is coming when we consider that they are parallel.

 

[dilchan]

PLEASE HELP ME
WHAT ARE THE CONDITIONS FOR DIFFRACTION GRATING ??

The incident light ray/wave must be perpendicular to the grating.

 

[Raiyan3]

Someone please give me tips on how to solve questions related to Cathode Ray Oscilloscope. If explained with an example it would be much appreciated.

 

[Kawshiklfc]

can somebody help me in cie A - level physics paper 51 question number 2

 

[Kawshiklfc]

can somebody help me in cie A - level physics paper 51 question number 2​

​

 

[A.ELWY 7]

Someone please give me tips on how to solve questions related to Cathode Ray Oscilloscope. If explained with an example it would be much appreciated.

as general they will ask for the period or frequency and a peak voltage...to find the frequency or period use the equation f=1/p, example: hw will give u a drawing showing a wave and as u know the drawing will be divided by as the question says 1cm squares and he will give u that the time base for example is 2ms cm-1, to find the frequency or the peroid find for one wavelength how many squares does it take, lets say 4...do the usual conversion 4m milli to centi and multiply the time base by the wavelength which is 4 to get the period..and as for the peak voltage he will state a y sensitivity lets say 5v cm-1..measure the amplitude of the wave according to the scale drawing and multiply it by the given sensitivity...
if u didnt undersatnd anything im happy to answer u again

 

[Unicorn]

what is the difference between spontaneous and random decay?

 

[Qamar Baloch]

Its nice to see that students of physics are very conscious to clear their concepts. I am expecting the same behavior from the students of A level ECONOMICS. If any of you is taking economics <Content Removed>

 

[Unicorn]

Its nice to see that students of physics are very conscious to clear their concepts. I am expecting the same behavior from the students of A level ECONOMICS. If any of you is taking economics <Content Removed>

Self promotion?
If you can't read this site is for students to help students not for teachers to go advertise for more money

 

[DragonCub]

what is the difference between spontaneous and random decay?

I think they describe decay from different points of view.
A decay is spontaneous since the substance can initiate decay by itself. It need not any special conditions.
A decay is random since the decay process is not programmed. The decay does not have any order i.e. which nucleus decays first and which one next. At every instant the nucleus/nuclei about to decay is chosen randomly.

 

[Unicorn]

I think they describe decay from different points of view.
A decay is spontaneous since the substance can initiate decay by itself. It need not any special conditions.
A decay is random since the decay process is not programmed. The decay does not have any order i.e. which nucleus decays first and which one next. At every instant the nucleus/nuclei about to decay is chosen randomly.

how can you intiate a decay then?

 

[DragonCub]

how can you intiate a decay then?

Not I, not you, not anyone. Decay starts by itself. It does not need a particular action as trigger. Once the nuclei have enough energy or are unstable enough, they begin decay on their own.

 

[Unicorn]

Not I, not you, not anyone. Decay starts by itself. It does not need a particular action as trigger. Once the nuclei have enough energy or are unstable enough, they begin decay on their own.

ok thanks