**21. If a mod-6 counter is constructed using 3 flip-flops, the counter will skip**

- 4 counts
- 3 counts
- 2 counts
- none of the counts

**22. A synchronous sequential circuit is to be designed to detect a bit sequence 0101 (overlapping sequence is included). Every time this sequence is detected, the circuit produces an output 1. What is the minimum number of states that the circuit must have ?**

- 4
- 5
- 6
- 7

**23. In order to build a MOD-12 counter, the minimum number of flip-flops needed is equal to**

- 12
- 4
- 3
- 1

**24. Which of the following counter results in least delay?**

- Ring counter
- Ripple counter
- Synchronous counter
- Asynchronous counter

**25. The one-bit memory element is called as**

- counter
- shift register
- flip flop
- multiplexer

**26. Flip flop is made up of an assembly of**

- counters
- PN junction diode
- thyristors
- logic gates

**27. All the flip-flops are triggered simultaneously with the same clock in ______ counter**

- both synchronous and asynchronous
- synchronous
- Asynchronous
- no need to triggering

**28. Asynchronous counters are often called ______ counters.**

- toggle
- ripple
- binary
- ring

**29. Mod-6 and mod-12 counters are most commonly used in**

- frequency counters
- multiplexed displays
- digital clocks
- power consumption meters

**30. The mod-10 counter is also referred to as a ________ counter.**

- decade
- johnson
- ring
- binary