Answer:
lacceleration is given by
a=F/m
With force acting on the object remained constant ,the acceleration is inversly proportional to mass of the object i.e with increase in mass =>acceleration decreases and with decrease in mass => acceleration increases.
a)
acceleration decreases
b)
acceleration increase
Despite current has a magnitude and a direction, like vectors, it is a scalar because it doesn't obey laws of vector addition. For instance, if we consider a junction of

in a circuit, and two currents entering this junction, we know that the resultant current is just the algebraic sum of the two currents, not the vector sum, so it is not a vector quantity.
A) 500 calories
B)5000 joules
C) 5 kilocalories
Answer is C
When light travels from a medium with higher refractive index to a medium with lower refractive index, the critical angle is the angle of incidence above which light is reflected only (no refraction occurs), and the value of this critical angle is given by

where n2 is the refractive index of the second medium and n1 is the refractive index of the first medium.
In this problem, the first medium is the glass (

), while the second medium is oil (

), therefore the critical angle is given by