1
GATE PI 2002
+2
-0.6
A
$$P - 2,\,\,Q - 1,\,\,R - 3,\,\,S - 4$$
B
$$P - 1,\,\,Q - 3,\,\,R - 4,\,\,S - 2$$
C
$$P - 4,\,\,Q - 2,\,\,R - 2,\,\,S - 3$$
D
$$P - 3,\,\,Q - 4,\,\,R - 1,\,\,S - 1$$
2
GATE PI 2002
+2
-0.6
In spot pulsed laser welding of aluminium plates (density $$= 2700kg/{m^3},$$ specific heat $$=896J/kg,$$ melting temp $$=933K,$$ latent heat of melting $$= 398\,\,kJ/kg)$$ at a temp of $${30^ \circ }C,$$ pulse with energy of $$0.5J$$ is focused onto an area of $$0.05m{m^2}.$$ If the entire energy is coupled into the material, what will be the depth of weld assuming the $$CS$$ area of the weld is circular and is uniform throughout its depth and only heat conduction in the direction of penetration
A
$$5.34mm$$
B
$$2.15mm$$
C
$$4.23mm$$
D
$$3.85mm$$
3
GATE PI 2002
+2
-0.6
Two different tools $$A$$ and $$B$$ having nose radius of $$0.6mm$$ and $$0.33mm$$ respectively are used to machine $$C-45$$ steel employing feed rate of $$0.2$$ $$mm/rev$$ and $$0.1mm/rev$$ respectively. The tool that gives better finish and the value of ideal surface roughness are
A
Tool $$A$$ and $$4.166$$ $$\mu m$$ respectively
B
Tool $$B$$ and $$3.78$$ $$\mu m$$ respectively
C
Tool $$A$$ and $$8.333$$ $$\mu m$$ respectively
D
Tool $$B$$ and $$8.333$$ $$\mu m$$ respectively
4
GATE PI 2002
Subjective
+5
-0
A cutting tool is designated in 'Orthogonal Rake System' as: $${0^ \circ } - {0^ \circ } - {6^ \circ } - {6^ \circ } - {25^ \circ } - {75^ \circ } - 0.8\,\,mm.$$\$
The following data were given
$${S_0} =$$ feed $$=0.12$$ $$mm/rev$$
$$T=$$ depth of cut $$=2.0$$ $$mm$$
$${a_2} =$$ chip thickness $$=0.22$$ $$mm$$
$${V_f} =$$ chip velocity $$=52.6$$ $$m/min$$
$${\tau _s} =$$ dynamic yield shear strength $$=400$$ $$MPa$$
$${P_z} =$$ main cutting force $$= {S_0}\,t\,{\tau _s}\left( {\zeta \,\sec y - \tan \gamma + 1} \right)$$

Where $$\zeta =$$ chip reduction coefficient and $$\gamma =$$ orthogonal rake.
The main cutting force $$\left( {{P_z}} \right)$$ and cutting power assuming orthogonal machining are

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