All Exams Test series for 1 year @ ₹349 only
Question

A 4 KB EPROM is organized with 8 data lines. How many address lines does it have?

This question was previously asked in
RRB JE 2025 CBT 2 Mechanical and Allied Engg Question Paper English (2-Jul-2026) (Shift-1)
The correct answer is

12

This is a memory-organisation problem. A memory chip is described as (number of locations) × (bits per location). The address lines select which location, and the data lines carry the contents of that location. The number of distinct locations that n address lines can select is 2n, so the address-line count is fixed by how many locations there are — not by how wide each location is.

Given: a 4 KB EPROM with 8 data lines (each location holds 8 bits = 1 byte).

Step 1 — find the number of locations. Since each location stores 1 byte, 4 KB corresponds to 4096 byte-locations:

  • 4 KB = 4 × 1024 = 4096 locations = 212

Step 2 — find the address lines:

  • Number of address lines = log2(4096) = 12

So the chip is organised as 4096 × 8: 12 address lines uniquely select one of 4096 bytes, and 8 data lines transfer that byte.

Why the other answers are wrong: 8 confuses the data width with the address width — the 8 refers to bits per location, not addressing. 10 would only address 210 = 1024 locations (1 KB), too few. 14 would address 214 = 16384 locations (16 KB), far more than needed. Only 12 lines give exactly 4096 locations.

Was this answer helpful?

Important Questions from Memory Address and Capacity

  1. A single unit which is composed of small group of bits is known as-

  2. Which of the following memories uses one transistor and one capacitor as a basic memory unit

  3. Minimum number of bits needed to address 2000 memory location are

  4. _______ register in a PC holds the address of the location to be accessed.

  5. Addressing of a 32K × 16 memory is realized using a single decoder. The minimum number of AND gates required for the decoder is

Need Expert Advice?
Test Series
RRB JE img
Railways
RRB JE Prev. Yr. Paper (CBT 1 + CBT 2) Test Series
290 Tests 5 Tests Free
4515 Attempts
4.3(88)
English

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App