ISRO CSE 2014 PYQ

An activation record (stack frame) stores information needed for one procedure invocation, such as parameters, local variables, return address, saved registers, control/dynamic link, and possibly access/static links for non-local variables. The heap is a separate memory region used for dynamic allocation; it is not itself stored inside each activation record.

Let |A| and |B| denote the lengths of strings derived from A and B. A → a gives |A|=1 (odd). B → bbA adds two terminals, so B has odd length whenever A does. A → BaB combines two odd-length B strings with one a, giving odd length. Therefore A and B always derive odd-length strings, while S → AB has even length. The grammar cannot create three consecutive a’s because every recursive A expansion inserts B strings, each beginning with bb. However, four consecutive b’s are possible: B ⇒ bbA ⇒ bbBaB ⇒ bbbb... . Thus the statement claiming that four consecutive b’s never occur is false.

A plane parallel to a generator (side) of a right circular cone intersects one nappe in a parabola. A plane perpendicular to the cone’s axis gives a circle, while other oblique cuts can produce ellipses or hyperbolas depending on their orientation.

The first four bits 0100 identify IPv4. The next four bits 0010 encode IHL = 2, where IHL is measured in 32-bit words. That would imply a header length of 2$\times 4 = 8 bytes$. IPv4’s minimum header is 20 bytes (IHL=5), so this header length is invalid and the packet should be discarded/rejected. The TTL and protocol fields cannot be inferred from these first eight bits.