Physics, Chemistry and Biology: Post your doubts here!

[Khadu33]

Thats stupid
The mass of ice that melted when the heater was on is 16.3...

oky do as u knw its much better dea

 

[Khadu33]

am following the concept that i was taught

oky do as u knw its much better dea

 

[Khadu33]

if i may ask why during specific heat capacity why do we subtract the temp

 

[Osman Kaleem]

I suspect the formula for Refractive index is switched where R.I = Sin i / Sin r ( for light rays travelling from less to more dense medium ) and R.I = Sin r / Sin ( for light rays travelling from more to less dense medium)

Yes u r right

 

[Osman Kaleem]

Thanks for the correction

 

[Osman Kaleem]

No problem, Osman! Thanks for the formulas anyway!

Welcome anytime

 

[Aayan Muttaqi]

yes but y r we subtracting the masses

I found a reasonable, or more so, a correct explanation.
You see, 16.3 g of ice melted due to the heat from the heater and the surrouding as well. For the further 2 minutes, it was just to show how much ice would melt due to energy from the surroundings only. Therefore, the actual mass of ice which actually melted due to the heater in 2 minutes is 16.3-2.1=14.2 g.

 

[Ayesha Asif333]

I found a reasonable, or more so, a correct explanation.
You see, 16.3 g of ice melted due to the heat from the heater and the surrouding as well. For the further 2 minutes, it was just to show how much ice would melt due to energy from the surroundings only. Therefore, the actual mass of ice which actually melted due to the heater in 2 minutes is 16.3-2.1=14.2 g.

I am baffled to see how mind boggling these ques can become at times
that's a fairly accurate and convincing explanation so thank you for bringing to our knowledge this idea and showing us the amount of ugliness hidden in this subj

 

[Aayan Muttaqi]

I am baffled to see how mind boggling these ques can become at times
that's a fairly accurate and convincing explanation so thank you for bringing to our knowledge this idea and showing us the amount of ugliness hidden in this subj

It was my pleasure, you are welcome.
There was also another question. It was about some gas trapped in a syringe. The syringe's piston was not sealed i.e. it could move. The question was when the temperature is increased , state the effect on the pressure of the gas.
Took me some time to get my head around this.

 

[Ayesha Asif333]

It was my pleasure, you are welcome.
There was also another question. It was about some gas trapped in a syringe. The syringe's piston was not sealed i.e. it could move. The question was when the temperature is increased , state the effect on the pressure of the gas.
Took me some time to get my head around this.

the volume of the gas in the syringe will increase as the temperature increases and the pressure would remain the same ?

 

[Adeen Atif]

Guys! Any idea about b(ii)

 

[Adeen Atif]

the volume of the gas in the syringe will increase as the temperature increases and the pressure would remain the same ?

Yes , I think thats the answer

 

[Adeen Atif]

I am baffled to see how mind boggling these ques can become at times

TBH I find these heat capacity one question very easy .But when it comes to barometer and speed time graphs then physics starts acting as a problem for me.

 

[Ayesha Asif333]

View attachment 62218 View attachment 62219
Guys! Any idea about b(ii)

P1 V1 = P2 V2
15 * 12 = P2 * 4

= 45

760 - 45 = 715 since they asked the ap given by teh barometer

what's the 720 in the ms for..i don't really know..

 

[Ayesha Asif333]

TBH I find these heat capacity one question very easy .But when it comes to barometer and speed time graphs then physics starts acting as a problem for me.

TBH with you, unfortunately i like phy with the whole of my heart but physics doesn't like me back
i think magnetism and radiation is the easiest bit
and yes, not only is the speed time graph ques a nuisance in phy but it is there in maths too and i remember, this ques came in the maths paper and i had to do alot of cutting and thinking

 

[Adeen Atif]

TBH with you, unfortunately i like phy with the whole of my heart but physics doesn't like me back
i think magnetism and radiation is the easiest bit
and yes, not only is the speed time graph ques a nuisance in phy but it is there in maths too and i remember, this ques came in the maths paper and i had to do alot of cutting and thinking

Same!
These graphs are like the only reason I hate physics.Or else I like it

 

[Adeen Atif]

P1 V1 = P2 V2
15 * 12 = P2 * 4

= 45

760 - 45 = 715 since they asked the ap given by teh barometer

what's the 720 in the ms for..i don't really know..

I solved it long time ago and I got 720.Now I forgot how I solved and Im stuck

 

[Ayesha Asif333]

I solved it long time ago and I got 720.Now I forgot how I solved and Im stuck

Many of us tried this ques but didn't get 720, so we stick to our own method
besides the subtraction for the upper part part of this ques is clearly wrong in the ms

 

[Adeen Atif]

Many of us tried this ques but didn't get 720, so we stick to our own method
besides the subtraction for the upper part part of this ques is clearly wrong in the ms

Ok

 

[Adeen Atif]

Guys,have u solved paper of 2017 feb march?