# Physics MCQs GK objective Questions GK test Set – 31

## Question 1.

Which one of the following has the highest value of specific heat?

A. Glass
B. Copper
D. Water

Ans: D. Water

## Question 2.

Which of the following represents a relation for ”heat lost = heat gained’?

A. Principle of thermal equilibrium
B. Principle of colors
C. Principle of calorimetry
D. Principle of vaporization

Ans: C. Principle of calorimetry

## Question 3.

Find the resistance (in mega) of a wire of length 20m, cross sectional area 1 cm2 and made of a material of resistivity 200m.

A. 40
B. 4000
C. 80
D. 2000

Ans: A. 40

## Question 4.

Water cannot be used to extinguish fire caused by electric current, because

A. It may cause electrocution
B. It may cause hydrolysis
C.It may cause electrolysis
D. It may spoil the wiring

Ans: A. It may cause electrocution

## Question 5.

Water is not suitable as a calorimetric substance because it :

A. Has high specific heat
B. Is a good conductor
C. Has high boiling point
D. Low latent heat of vapourization

Ans: A. Has high specific heat

## Question 6.

Q = mcdT refers to

A. Enthalpy formula
B. Heat Transfer formula
C. Specific Heat formula
D. Heat of Vaporization

Ans: C. Specific Heat formula

## Question 7.

A copper wire of radius r and length l has a resistance of R. A second copper wire with radius 2r and length l is taken and the two wires are joined in a parallel combination. The resultant resistance of the parallel combination of the two wires will be

A. 5 R
B. 5 R/4
C. 4 R/5
D. R/5

Ans: D. R/5

## Question 8.

Brightness of bulb depends on voltage or current?

A. Current
B. Voltage
C. Both A & B
D. None

Ans: C. Both A & B

## Question 9.

Water is used in car radiator because of its

A. Low density
B. Easy availability
C. High specific heat capacity
D. Low boiling point

Ans: C. High specific heat capacity

## Question 10.

Steam at 100°C causes more severe burns than water at 100°C because

A. Steam has no specific heat capacity
B. Steam has latent heat of vaporisation
C. Water has no specific heat capacity
D. Water has latent heat of fusion

Ans: B. Steam has latent heat of vaporisation

## Question 11.

Which of the following is a good conductor of heat but a bad conductor of electricity ?

A. Celluloid
B. Rubber
C. Asbestos
D. Mica

Ans: D. Mica

## Question 12.

The resistance of a conductor is inversely proportional to its:

A. Length
B. Resistivity
C. Temperature
D. Area of cross section

Ans: D. Area of cross section

## Question 13.

How much mechanical work must be done to completely melt 1 gram of ice at 0°C ?

A. 4.2 J
B. 80 J
C. 336 J
D. 2268 J

Ans: B. 80 J

## Question 14.

No current will flow between two charged bodies if they have the same

A. Resistance
B. Charge
C. Potential
D. Charge/ potential ratio

Ans: C. Potential

## Question 15.

When a number of resistors are connected in series in a circuit, the value of current:

A. Increases
B. Becomes half
C. Decreases
D. Remains the same

Ans: D. Remains the same

## Question 16.

Which one of the following is an ohmic conductor?

A. Germanium
B. Silicon
C.Carbon
D. Silver

Ans: D. Silver

## Question 17.

Water pipes in hilly areas often burst on a cold frosty night, because

A. The material of which pipes are made contracts due to cold and so breaks
B. Water in the pipes freezes and on freezing water expands, so pipes break
C. Frost makes the pipes rusty, so they break
D. None of these

Ans: B. Water in the pipes freezes and on freezing water expands, so pipes break

## Question 18.

Two metallic wires made from copper have same length but the radius of wire 1 is half of that of wire 2. The resistance of wire 1 is R. If both the wires are joined together in series, the total resistance becomes

A. 2R
B. R/2
C. 5R/4
D. 3R/4

Ans: C. 5R/4

## Question 19.

A good conductor while carrying current is

A. Alternately charged positive and negative
B. Negatively charged
C. Positively charged
D. Electrically neutral

Ans: B. Negatively charged

## Question 20.

What is the effective resistance (in O) of two resistors 20 O and 30 O connected in parallel?

A. 50
B. 12
C. 24
D. 36

Ans: B. 12

## Physics GK MCQs all set

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