KVPY Stream-SA (Class 11) Physics: Questions 75 - 78 of 242

Get 1 year subscription: Access detailed explanations (illustrated with images and videos) to 242 questions. Access all new questions we will add tracking exam-pattern and syllabus changes. View Sample Explanation or View Features.

Rs. 200.00 or

Question number: 75

» Current Electricity » Electrical Energy and Power

Appeared in Year: 2013

MCQ▾

Question

If the current through a resistor in a circuit increases by 3%, the power dissipated by the resistor,

Choices

Choice (4) Response

a.

increases approximately by 3%

b.

decreases approximately by 3%

c.

increases approximately by 6%

d.

increases approximately by 9%

Question number: 76

» Ray Optics » Lens Maker's Formula and Lens Formula

MCQ▾

Question

A convex lens made of material of refractive index 1.45 is immersed in a medium of refractive index 2.2. The two surfaces of the convex lens have the same radius of curvature 0.6 m. The lens will behave as a,

Choices

Choice (4) Response

a.

Convergent lens of focal length 0.44 m.

b.

Divergent lens of focal length 0.44m

c.

Convergent lens of focal length 0.88 m

d.

Divergent lens of focal length 0.88 m.

Question number: 77

» Properties of Solids & Liquids » Temperature

MCQ▾

Question

The energy emitted per second by a black body at 300 C is 15 J. When the temperature of the black body is raised to 2500 C, the energy per second will be

Choices

Choice (4) Response

a.

85 J

b.

130 J

c.

133 J

d.

88 J

Question number: 78

» Thermodynamics » Thermal Equilibrium

MCQ▾

Question

A magnesium piece of mass 30 g initially at 350 °C is dipped quickly and taken out of 1 kg of water, initially at 45° C. if the temperature of the magnesium piece immediately after being taken out of the water is found to be 180°C, what is the temperature of the water then? (Specific heat capacities of magnesium and water are 1020 J kg–1 K–1 and 4200 J kg–1, respectively. )

Choices

Choice (4) Response

a.

23.5°C

b.

48°C

c.

38.65°C

d.

46.24°C

Sign In