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An electric heater supplies heat to a system at a rate of 100W. If system performs work at a rate of 75 joules per second. At what rate is the internal energy increasing?

By law of conservation of energy, Total energy is given by Total energy= Work done + Internal Energy 100=75+U=25 J/s... View Article

Two oxides of a metal contain 50% and 40% of the metal, respectively. The formula of the first oxide is MO. Then, the formula of the second oxide is : a) MO2 b) M2O c) M2O5 d) M2O3

Option d) M2O3

A sample of air is saturated with benzene (vapour pressure =100 mm Hg at 298 K) at 298K, 750mm Hg pressure. If it is isothermally compressed to one third of its initial volume, the final pressure of the system is:

The total pressure = vapour pressure of benzene + pressure of air. The pressure of air =750−100=650 mm of Hg.... View Article

Find the number of terms of the AP 54, 51, 48, …… so that their sum is 513

a=54 d=51−54=−3 Sn=513 Sn=n/2[2a+(n−1)d] 513=n/2[2(54)+(n−1)(−3)] 1026=n[108−3n+3] 1026=n[111−3n] 3n2−111n+1026=0 n2−37n+342=0 n2−18n−19n+342=0 (n−18)(n−19)=0 n=18,19 T18=a+17d=54+17(−3)=3 T19=a+18d=54+18(−3)=0

Write the successor of the following numbers 378915

Successor of the number 378915 is: 378915 +1 = 378916

Where the main fuse in a house circuit is connected

The main fuse in a house circuit is connected to the live wire. The fuse has a high rating of... View Article

A horizontal disc rotating freely about a vertical axis through its center makes 90 revolutions per minute. A small piece of wax of mass m falls vertically on the disc and sticks to it at a distance r from the axis. If the number of revolutions per minute reduce to 60, then the moment of inertia of the disc is?

Let the moment of inertia of the disc is I. Initial angular momentum is L1=I1ω1=90I When the mass m sticks... View Article

In hire purchase ownership of the property is transferred to the hirer on the payment of the ————- installment. a) last b) third c) first d) second

Option a) last. In hire purchase, ownership of the property is transferred to the hire on the payment of the... View Article

The voltage gain of an amplifier with 9% negative feedback is 10. The voltage gain without feedback will be: a) 100 b) 90 c) 1.25 d) 10

Option a) 100Voltage gain =Av/1+β.Avwhere β=9/100=0.09, voltage gain = 1010=Av/1+9/100.AvAv=10/0.1=100

An analysis of chromosomal DNA using the southern hybrization technique does not use a) Autoradiography b) PCR c) Electrophoresis d) Blotting

Option b) PCR. Analysis of chromosomal DNA using the southern hybrization technique does not use PCR.

coal : heat : : wax : ? a) Energy b) Force c) Light d) Torch

Option c) Light

A metal cuboid of dimension 22 cm × 15 cm × 7.5 cm was melted and cast into a cylinder of height 14 cm. What is its radius a) 12 cm b) 7.5 cm c) 10.5 cm d) 14 cm

Option b) 7.5 cm. Radius is 7.5 cm

Which type of semiconductor is formed when silicon is doped with arsenic

An n-type extrinsic semiconductor is formed when silicon is doped with arsenic. This happens when silicon is doped with arsenic,... View Article

Two identical satellites are at the heights R and 7R from the earth’s surface. Then which of the following statement is correct: (R = Radius of the earth) a) Ratio of total energy of both is 4 b) Ratio of total energy of both is 5 c) Ratio of potential energy of both 9 d) The ratio of kinetic energy of both is 6

Option a) Ratio of total energy of both is 4.

Two forces, while acting on a particle in the opposite directions, have the resultant of 10N. If they act at right angles to each other, the resultant is found to be 50N. Find the two forces.

Parallelogram law of vector addition consider F1 & F2 as the two forces acting in the opposite direction. By parallelogram... View Article

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