Electrons have a negative charge.
Explanation:
Given that,
The voltages across them are 40,50 and 60 volts respectively, and the charge on each condenser is 6×10⁻⁸ C.
(a) Capacitance of capacitor 1,

Capacitance of capacitor 2,

Capacitance of capacitor 3,

(b) The equivalent capacitance in series combination is :

Hence, this is the required solution.
Answer: The volume is decreasing at a rate of 80 cm3/min
Explanation: Please see the attachments below
The statement “Impulse is a vector quantity” is true about Impulse.
Answer: Option B
<u>Explanation:
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The object’s action by applied force in a particular time interval, there happens changing in momentum called impulse. It is denoted by a symbol ‘J’ or ‘imp’ and expressed in a unit ‘Ns’. As impulse depends on the acted force, when a collision arises from front, behind or side, the force’s direction would be differed.

So, from this option A is false as impulse is not a force but changing momentum. The unit is not Newton, it is Newton second (Ns). The force direction differs (impulse direction) for each cases of collision, so option D also false. Hence, option B seems to be correct. Vector quantity deals with both direction and magnitude and important in motion study.
The momentum of the truck is given by:
p = mv
p = momentum, m = mass, v = velocity
There isn't too much work to do here; the truck is at rest, therefore its velocity is 0. This means the product of m and v is 0, giving the momentum as 0.