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(C) Power requirement for $1$ laptop,$P_1 = 90 \,W$.Total power requirement for $10$ laptops,$P = 10 	imes 90 = 900 \,W = 0.9 \,kW$.Since the $UPS$ i

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$I$ and $III$ only

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(C) Power requirement for $1$ laptop,$P_1 = 90 \,W$.Total power requirement for $10$ laptops,$P = 10 	imes 90 = 900 \,W = 0.9 \,kW$.Since the $UPS$ is rated at $1 \,kVA$,it can handle $900 \,W$ (assuming power factor $\approx 1$),so statement $I$ is correct.In $5 \,h$,electrical energy used by all laptops,$E = P 	imes t = 0.9 \,kW 	imes 5 \,h = 4.5 \,kWh$.Cost of electricity = $4.5 \,kWh 	imes ₹ 5.00/kWh = ₹ 22.50$. Thus,statement $III$ is correct.For an input voltage of $220 \,V$,the current drawn by $10$ laptops is $I = P/V = 900 \,W / 220 \,V \approx 4.1 \,A$.Since $4.1 \,A > 3 \,A$,a $3 \,A$ fuse will blow. Thus,statement $II$ is incorrect.Therefore,statements $I$ and $III$ are correct.

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