Actually you're more likely to find a capacitor in parallel in a charging circuit to increase its charging efficiency (as shown in this *battery charger circuit) but that's ... errr ... beyond the O Level Physics syllabus.

*ignore the diode for the optional LED indicator - even then there's a 10 kΩ resistor in series to prevent short circuiting

childlike93: Regarding the direction of the charging current, we don't really have to think about how it charges (chemical energy and all) when it's already been defined in the question when it said "This (charging) is done by passing a current through the battery in the opposite direction to that when it is discharging."

We know that the current flows anti-clockwise when the battery discharges (conventional current flows out of its positive terminal). Thus the charging current has to be clockwise.

As mentioned earlier it's easier to consider the conventional current since the diode symbol's 'arrow' is pointing in the direction of the conventional current.

random123: I've taken the liberty to draw out the following diagrams for the options (didn't do option C since it's obvious that a brighter object will not help in focussing its image on the screen:

To focus the image on the screen i.e. what we want are the light rays to converge exactly on the screen. Else it will be blurred.

If you've played around with the application, moving the object away from the lens in Option A will cause the rays to converge somewhere along the principal axis that is nearer to its focal point F, but what we actually need is for them to converge at the screen which is farther away from F.

Moving the screen away from the lens in Option B will obviously make it worse, as shown in the diagram

In Option D, a (typically) thinner lens with a longer focal length causes the rays to bend less and hence converge farther away. Thus by picking an appropriate lens with a longer focal length, we can 'aim' the light rays to converge exactly on the screen.

Anyone notice that this is a classic scenario of myopia aka short-sightedness? The 'screen' is actually your retina!

ds(:: Yes the two (identical) cells connected in parallel in the circuit in Option A will yield the same potential difference across the circuit i.e. the voltage is the same as that of a single cell. Hence the current will still be 1A.

P.S. While the voltage and current is unchanged, do note that connecting cells in parallel actually helps them last longer, since each cell only has to supply a fraction of the 1A current demanded by the lamp. Now you know why the Duracell Bunny can last so long

For Q21, try moving the object away from the lens in this little application

using the application it shows when object moved away from focal length, image becomes smaller, therefore it is focus, since smaller = focus?
so answer should be A?

and if the object falls into smaller than the focal length, then image formed would be virtual and not focused in the case when lengthening focal length of lens.

At this moment the best thing I can do is the reproduce the answers as follows:

Q1-5: C D D C B
Q6-10: C A A B C
Q11-15: B C A A B
Q16-20: B B D D B
Q21-25: D D C C B
Q26-30: C D A D C
Q31-35: C D C D A
Q36-40: C B D D D

However the pdf file (with all the diagrams and workings) looks OK on our side. Have you tried to view it on another computer? Which pdf reader (and version) are you using?