tough Digital Electronic/Circuits questions and answers on “Random Access Memory-3”.
1. Dynamic RAM is more preferable than static RAM, why?
A. DRAM is of the lowest cost, lowest density
B. DRAM is of the highest cost, reduced size
C. DRAM is of the lowest cost, highest density
D. DRAM is more flexible and lowest storage capacity
Answer: C
Clarification: The Dynamic Random Access Memory is the lowest cost, highest density random access memory available. Nowadays, computers use DRAM for main memory. However, it’s access time is more compared to SRAM.
2. The memory size of DRAM is ____________
A. 1 to 100 MB
B. 512 to 1024 MB
C. 64 to 512 MB
D. 16 to 256 MB
Answer: D
Clarification: The Dynamic Random Access Memory is the lowest cost, highest density random access memory available. Nowadays, computers use DRAM for main memory. However, it’s access time is more compared to SRAM. The memory size of DRAM lies between 16 to 256 MB.
3. The DRAM stores its binary information on __________
A. MOSFET
B. Transistor
C. Capacitor
D. BJT
Answer: C
Clarification: Capacitor has high storing capability only, so DRAM stores its binary information in the form of electric charges on capacitors. However, DRAM takes more time time to access data.
4. Most modern operating systems employ a method of extending RAM capacity, known as __________
A. Magnetic memory
B. Virtual memory
C. Storage memory
D. Static memory
Answer: B
Clarification: Most modern operating systems employ a method of extending RAM capacity, known as virtual memory. Virtual memory is seen as part of main memory but is actually a secondary memory.
5. DRAM uses of integrated MOS capacitors as _______ instead of a flip-flop.
A. Storage cell
B. Memory cell
C. Dynamic cell
D. Static cell
Answer: B
Clarification: DRAM uses of integrated MOS capacitors as memory cell instead of a flip-flop. The advantage of this cell is that it allows very large memory arrays to be constructed on a chip at a lower cost per bit than in static memories.
6. What is the disadvantage of MOS capacitor in DRAM?
A. It can’t hold the data till a long period
B. It doesn’t holds the charge till a long period
C. It is highly densed
D. It is not flexible
Answer: B
Clarification: The disadvantage of MOS capacitor in DRAM is that it can’t hold the stored charge over a long period of time and it has to be refreshed every few millisecond. Thus, DRAM is slow in operation.
7. The dynamic RAM offers __________
A. High power consumption, large storage capacity
B. Reduced power consumption, large storage capacity
C. Reduced power consumption, short storage capacity
D. High power consumption, short storage capacity
Answer: B
Clarification: The dynamic RAM offers reduced power consumption and large storage capacity in a single memory chip. With the availability of such high packing density memory ICs, the capacity of memory will continue to grow. However, it’s access time is more and thus operation is slow.
8. The main memory of a PC is made of __________
A. Cache
B. Dynamic RAM
C. Static RAM
D. Both cache and dynamic RAM
Answer: D
Clarification: The main memory of a PC is made of cache and DRAM. DRAM offers reduced power consumption and large storage capacity in a single memory chip.
9. Virtual memory consists of __________
A. SRAM
B. DRAM
C. Magnetic memory
D. Main Memory
Answer: A
Clarification: Most modern operating systems employ a method of extending RAM capacity, known as virtual memory which consists of SRAM.
10. Dynamic RAM is used as main memory in a computer system as __________
A. It has a lower cell density
B. It needs refreshing circuitry
C. Consumes less power
D. Has higher speed
Answer: D
Clarification: Dynamic RAM is used as main memory in a computer system as it has a higher speed due to the presence of MOSFET technology. However, it’s access time is more compared to SRAM and operation is slow.
11. Cache memory acts between __________
A. RAM and ROM
B. CPU and RAM
C. CPU and Hard Disk
D. CPU and ROM
Answer: B
Clarification: In a computer, cache memory acts between CPU and RAM.
12. Which characteristic of RAM memory makes it not suitable for permanent storage?
A. Unreliable
B. Too slow
C. Too bulky
D. It is volatile
Answer: D
Clarification: RAM is volatile. Therefore, it stores data only as long as the d.c power is on.
13. Why do a DRAM employ the address multiplexing technique?
A. To reduce the number of memory locations
B. To increase the number of memory locations
C. To reduce the number of address lines
D. To increase the number of address lines
Answer: C
Clarification: A Dynamic RAM usually employs a technique called address multiplexing to reduce the number of address lines and thus the number of input/output pins on the IC package.
14. An address multiplexing in DRAM is of _____ bits.
A. 10240
B. 15289
C. 16384
D. 17654
Answer: C
Clarification: A Dynamic RAM usually employs a technique called address multiplexing to reduce the number of address lines and thus the number of input/output pins on the IC package. Address multiplexing has 214 = 16384 bits.
15. What is a sense amplifier?
A. It is an amplifier which converts ac current into dc current
B. It is an amplifier which lowers the input voltage
C. It is an amplifier which increases the input voltage
D. It is an amplifier which converts the low voltage to a sufficient voltage
Answer: D
Clarification: A sense amplifier for each column is necessary to convert from the low voltage and low energy to a sufficient level on the I/O data line.
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