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A main memory unit with a capacity of 4 megabyte is built using 1 M × 1 bit DRAM chips. Each DRAM chip has 1 rows of cells with 1 k cells in each row. The time taken for a single refresh operation is 100 ns. The time required to perform one refresh operation on all the cells in the memory unit is
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- 100 ns
- 100 * 210 ns
- 100 * 220 ns
- 3200 * 220 ns
- 100 ns
Correct Option: D
One chip contains 106 bits.to build 4MB capacity MM 32 chips will be required there are 1K × 1K cells in each chip i.e. 106 cellshence time taken to refresh a single chip 106 × 100 ns.there are 32 such chips hence 32 × 106 × 100 ns time will be taken i.e. 3200 × 220 ns
