# KVPY (Kishore Vaigyanik Protsahan Yojana) Stream-SA (Class 11) Physics: Questions 75 - 78 of 253

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## Question number: 75

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

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

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

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

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