# Multiple Choice (1 Viewer)

#### RealiseNothing

##### what is that?It is Cowpea
Fairly sure 17 is D, so you will probably get 19/20.

#### spongebob1

##### New Member
14 is c? V= Ed where V is constant? Isnt that a linear relationship so a straight line

#### Menomaths

##### Exaı̸̸̸̸̸̸̸̸lted Member
1) b
2) d
3) a
4) a
5) d
6) c
7) a
8) d
9) b
10) c
11) b
12) a
13) d
14) b
15) a
16) d
17) b
18) c
19) c
20) b

Tossing up between 17 b or d.. probably determines my 19/20 or 20/20
Sadly 17 is not b #### Randox

##### Member
14 is c? V= Ed where V is constant? Isnt that a linear relationship so a straight line
I put c. That was my thinking behind it

#### RealiseNothing

##### what is that?It is Cowpea
14 is c? V= Ed where V is constant? Isnt that a linear relationship so a straight line
E=V/d

#### MATHmaster

##### Member
14 is c? V= Ed where V is constant? Isnt that a linear relationship so a straight line
That's a hyperbola

#### spongebob1

##### New Member
Yeh rearrange it for v and v is a constant?

#### spongebob1

##### New Member
V=Ed isnt a hyperbola...

#### MATHmaster

##### Member
E = V/d
You're graphing E on the y-axis and d on the x-axis
let E = y and d = x
Hence y = V/x where V is constant
Therefore it is a hyperbola

#### anomalousdecay

E = V/d
You're graphing E on the y-axis and d on the x-axis
let E = y and d = x
Hence y = V/x where V is constant
Therefore it is a hyperbola
You're right. It is a hyperbola. Listen to 4-unit not 2-unit.

##### Member
14/20 and stuffed up the photocell. Band 5 is gonna be a mission now.

Feel so bad after getting a 19/20 in Chemistry.
I know that feeling.

#### anomalousdecay

I know that feeling.
And Chem is suppossed to be harder.

I'm gonna say this now, might be too early:

"I'm gonna miss Chemistry in uni"

HSC Chemistry is so much more enlightening than the philosophy of HSC Physics.
At least engineering uni physics is nothing like HSC.

#### Hoskiies

##### Member
1) b
2) d
3) d
4) a
5) d
6) c
7) a
8) d
9) b
10) c
11) b
12) a
13) b
14) b
15) a
16) c
17) c - Not sure, because the X axis says motor speed not time, So as motor speed increases shouldn't torque also increase?
18) c
19) c
20) b

#### yasminee96

##### Active Member
And Chem is suppossed to be harder.

I'm gonna say this now, might be too early:

"I'm gonna miss Chemistry in uni"

HSC Chemistry is so much more enlightening than the philosophy of HSC Physics.
At least engineering uni physics is nothing like HSC.
I made this really stupid decision to drop chemistry and keep physics.
kml

#### uart

##### Member
1) b
2) d
3) a
4) a
5) d
6) c
7) a
8) d
9) b
10) c
11) b
12) a
13) d
14) b
15) a
16) d
17) b *Controversial
18) c
19) c
20) a * Should be "b"
Good work RN, all correct there except for 20. Answer for 20 is b.

Reason why 20 is b: The frequency of the light is c/lambda = 6.7E14, so *only* metal "X" is illuminated above the threshold for electron emission, so the number of emitted electrons increases only in metal "X". The number of electrons emitted from metal "Y" will remain zero both before and after the increase in intensity.

Note that Q17 is controversial. The answer to 17 could be either "b" or "d" depending on what assumptions are made. See my post below.

Last edited:

#### Menomaths

##### Exaı̸̸̸̸̸̸̸̸lted Member
Good work RN, all correct there except for 20. Answer for 20 is b.

Reason why 20 is b. The frequency of the light is c/lambda = 6.7E14, so only metal "X" is illuminated above the threshold for electron emission. So the number of electron increase in metal "X" only, the electrons emitted from metal "Y" will remain zero both before and after the increase in intensity.
There's one more wrong answer in there.

#### anomalousdecay

I made this really stupid decision to drop chemistry and keep physics.
kml
I don't know. Hope that I can somehow integrate chemistry into electrical.
It only looks good in terms of pv cells and materials used and batteries. Worst compromise of wanting to do chemical and electrical at the same time.

And you probably would have benefited more with chem for med.

#### uart

##### Member
There's one more wrong answer in there.
Are you referring to Q17, I was just about to discuss that. That question is controversial in my opinion.

The answer for 17 is b if motor is supplied by constant current, but is d if the motor is supplied by a constant voltage source.

The question didn't specify whether the voltage was constant or if the current was constant in this case, so it's quite ambiguous. I agree that constant voltage sources are more commonly used than constant current, so it could be argued that "d" is *more* correct than "b". To be honest though, it's hard to know for sure what assumption they were expecting the students to make here and how they will mark that one.

Last edited:

#### Menomaths

##### Exaı̸̸̸̸̸̸̸̸lted Member
Are you referring to Q17, I was just about to discuss that. That question is controversial in my opinion.

The answer for 17 is b if motor is supplied by constant current, but is d if the motor is supplied by a constant voltage source.
The answer is what Fizzy said 