**Part
I (10 marks)**

#### This is a ISC class XI practice test for computer students. The topics covered in this paper are Boolean Algebra, Logic gates, Number conversions

**Matrix programs**

**(Attempting
all the answers in this part is compulsory)**

- Convert the following Hexadecimal to binary & decimal [4]
- F8 b. 1A c. 3B d. ACE

- Perform binary multiplication on the following [2]
- 1010*101 b.1101*0101

- Convert the following into decimal [4]
- 1101010 b. 01.111 c. 1001.00101 d. 1010111

**Part II (20
marks)**

isc class xi practice test**(Attempt any two questions)**

**Question**1.

- Explain with logic gate diagram why NAND & NOR gates are called universal gates? [5]
- Explain Full adder circuit with help of logic gate diagram, truth table, Boolean expression? [5]

- Draw logic gate diagram of (x+y+z).(xâ€™+y+zâ€™) using basic gates. [4]
- Explain what is truth table? [2]
- Draw logic gate diagram for the following using NOR gate
- Pâ€™Qâ€™+PQ+QR [4]

isc class xi practice test**Q3**Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â

- Prove that for the following using truth table? [4]
- A.(A+B)=A
- (A.B).Aâ€™=0

- Expand the following [3]

- ASCII
- EBCDIC
- ISCII 3. Explain the rule for binary subtraction? [3]