Questions

It is ABACUS.

Words formed are as below 

BUS
CAB
CUB
US

A Clock has a face, but no eyes. It has 3 hands i.e, hours, minutes and seconds hands but no arms.

Answer A is tempting because the problem focuses on changes. However, because we are talking about the elaboration of the product's characteristics, we are talking about scope changes, and therefore Answer B is the best answer. Answer C is also tempting because it is difficult to more forward on a project until the scope is clearly defined (especially in systems development projects), but with products and certain types of web development, scope changes can be frequent, and a formal scope management plan is needed. Answer D is true from a project perspective, but does not addres the scope issues.

90 D in RA means 90 Degrees in Right Angle. It is a logic question which is to be eloborated.

Some more of its kind are:

1. 52 W in a Y     -    52 Weeks in a Year

2. 7 C in a R        -    7 Colours in a Rainbow

3. 9 P in SS

4. 5 C in an OF

5. 12 S of the Z

It will stop at a height where the weight of the balloon with contents is equal to the weight of air displaced by it, i.e , when the upthrust is equal to the downthrust. The question of bursting will depend on how much difference of pressure inside and outside , the material of the balloon can withstand. It is assumed the balloon is filled with a lighter than air gas like hydrogen or helium.

The resistance of metallic conductors e.g, platinum, increases with rise of  temperature . The increase in temperature results in a decrease of current which can be recorded in a galvanometer if the conductor is included in an electrical circuit. Thus the temperature can be known; platinum resistance thermometer is used generally for accurate scientific work. When two dissimilar metals are joined at the ends, and these ends are subjected to a difference of temperature, a current flows through the metals. Greater the difference of temperature , greater the current. So the curent strength can form the basis for measuring the difference in temperature. And when one of these temperatures is known, we can calculate the other.