Analysis of Statements
Statement P: DRAM requires refreshing because it uses capacitors to store bits.
This statement is true. DRAM cells store data as electrical charges in capacitors, and these charges dissipate over time due to leakage, necessitating periodic refreshing to maintain data integrity.
Statement Q: SRAM does not require refreshing because it uses flip-flops instead of capacitors.
This statement is true. SRAM cells utilize flip-flops, which are bistable latching circuits, to store data. These circuits hold the data as long as power is supplied, eliminating the need for refreshing.
Statement R: DRAM is faster than SRAM because it needs less frequent access.
This statement is false. SRAM is generally faster than DRAM because it does not require refreshing cycles, which introduce delays in DRAM operations. The need for less frequent access does not inherently make DRAM faster; in fact, the refreshing requirement makes it slower.
Statement S: DRAM is more suitable for main memory than SRAM due to its density.
This statement is true. DRAM cells are simpler and require fewer components (typically one transistor and one capacitor per bit) compared to SRAM cells (typically six transistors per bit). This allows for higher storage density in DRAM, making it more cost-effective and suitable for the large capacities required in main memory.
Conclusion
Based on the analysis of each statement:
- Statement P is true.
- Statement Q is true.
- Statement R is false.
- Statement S is true.
Therefore, the option that accurately reflects the truthfulness of these statements is the one where P, Q, and S are true, and R is false.
Final Answer
The correct option is 
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