its kinetic energy on the ground
twice its initial potential energy
its initial potential energy
half its initial potential energy
Correct answer is D
At the height of 10m, its total energy is potential, given by P.E. = mgh = 1 x 10 x 10 = 100J.
But as the stone descends, its potential energy decreases, while its kinetic energy increases.
Half way during the fall, (h = 5m), its P.E. = 50J, and consequently, its K.E. should be 50J, such that from the principle of conservation of energy, the total energy of the stone at any instant should be conserved.
380mmHg
570mmHg
190mmHg
480mmHg
Correct answer is B
(p - 760)/(0 - 760) = (h - 0)/(80 - 0)
∴ (p - 760)/-760 = (20 - 0)/80
80(p-760) = -760(20-0)
∴80p - 60800 = -15200
80p = 60800 - 15200
80p = 45600
∴ p = 45600/80
p = 570mmHg
1.7V
2.0V
8.0V
15.0V
Correct answer is B
For a photoemitted electron,
eV = K.E.max, where V = stopping potential and K.E. = maximum kinetic energy of the photo emitted electron given by K.E. = Energy of incident rad - Work - function
= 5ev - 3ev = 2ev
∴ eV = 2eV
V = 2eV/e = 2V
∴ Stopping Potential = 2.0V
0.2N
0.8N
3.2N
8.0N
Correct answer is B
The force on the conductor is maximum when the conductor lies perpendicular to the field during which the maximum force is given as;
F = ILB = 0.8 x 2 x 0.5 = 0.8N
25%
33%
50%
75%
Correct answer is D
Efficiency = Output/input x 100/1
Efficiency = 3/(3+1) x 100/1
= 3/4 x 100/1 = 75%