RRB Technician Grade I (Signal) 19 Dec 2024 Shift 3 – Question Paper

Concept: Agni-Prime is the new-generation, canisterised ballistic missile of the Agni series developed by DRDO.

1. On 3 April 2024 DRDO and the Strategic Forces Command successfully flight-tested Agni-Prime from Dr APJ Abdul Kalam Island, Odisha.
2. Its range is 1,000–2,000 km; it is lighter than Agni-I/II and uses composite motor casings.
3. Surya is a proposed ICBM, Prahaar is a short-range tactical missile and Akash is a surface-to-air missile.

Yaad rakhein: Agni = ballistic (surface-to-surface); Akash = air-defence (surface-to-air).

Answer: (A) Agni Prime

Concept: Replace the letters by the given operators and apply BODMAS.

1. A = ÷, B = ×, C = +, D = −, so the expression becomes $15-12÷6+3\times 7$.
2. Division and multiplication first: $12÷6=2$ and $3\times 7=21$.
3. $15-2+21=34$.

Trick: Write the real symbols above the letters first, then solve left to right in BODMAS order – never solve in the written order.

Answer: (A) 34

Concept: GPU = Graphics Processing Unit – a special electronic circuit on the graphics card that accelerates graphics and image processing.

1. Statement i is false: GPU is not "Graphical User Interface" (that is GUI).
2. Statement ii is true – GPUs are built to accelerate and enhance computer graphics and image processing.
3. Statement iii is true – the GPU is an electronic circuit found on the graphics card.
4. Only the option containing ii and iii without i fits.

Trick: GPU ≠ GUI. GPU = hardware (Processing Unit), GUI = software (User Interface).

Answer: (C) Only ii and iii

Concept: In an isosceles triangle the angles opposite equal sides are equal; the three angles add to ${180}^{\circ }$.

1. $AC=BC$ ⇒ $\angle A=\angle B=\frac{2}{5}\angle C-9$.
2. Sum: $2(\frac{2}{5}C-9)+C=180$ ⇒ $\frac{9}{5}C=198$ ⇒ $\angle C={110}^{\circ }$.
3. $\angle A=\angle B=44-9={35}^{\circ }$.
4. $\frac{2(110)-3(35)+35}{2}=\frac{220-105+35}{2}=\frac{150}{2}={75}^{\circ }$.

Trick: Since $\angle A=\angle B$, the expression simplifies to $\frac{2C-2A}{2}=C-A=110-35=75$.

Answer: (B) ${75}^{\circ }$

Concept: Band gap energy ($E_g$) is the energy needed to move an electron from the valence band to the conduction band.

1. Standard values at room temperature: $E_g(\mathrm{G}\mathrm{e})\approx 0.67\text{eV}$, $E_g(\mathrm{S}\mathrm{i})\approx 1.1\text{eV}$, $E_g(\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s})\approx 1.43\text{eV}$.
2. Hence $E(\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s})>E(\mathrm{S}\mathrm{i})>E(\mathrm{G}\mathrm{e})$.
3. This is why Ge devices are more temperature-sensitive (smallest gap) and GaAs is used in LEDs/high-frequency devices.

Yaad rakhein: "Ge < Si < GaAs" – 0.7, 1.1, 1.4 eV (roughly increasing by 0.35).

Answer: (A) E(GaAs) > E(Si) > E(Ge)