### NEET Physics - New -

#### Question - 1

Two wires are made of the same material and have the same volume. The first wire has cross-sectional area A and the second wire has cross-sectional area 3A. If the length of the first wire is increased by Δlon applying a force F, how much force is needed to stretch the second wire by the same amount?

• A 9 F
• B 6 F
• C 4 F
• D F

#### Question - 2

The bulk modulus of a spherical object is 'B'. If it is subjected to uniform pressure 'p', the fractional decrease in radius is :

• A B/3p
• B 3p/B
• C p/3B
• D p/B

#### Question - 3

The Young's modulus of steel is twice that of brass. Two wires of the same length and same area of cross section, one of steel and another of brass, are suspended from the same roof. If we want the lower ends of the wires to be at the same level, then the weights added to the steel and brass wires must be in the ratio of:

• A 4:1
• B 1:1
• C 1 :2
• D 2:1

#### Question - 4

The approximate depth of an ocean is 2700 m. The compressibility of water is 45.4 x 10-11 P and density of water is 103 kg/m3. What fractional compression of water will be obtained at the bottom of the ocean?

• A 0.8 x 10-2
• B 1.0 x 10-2
• C 1.2 x 10-2
• D 1.4 x 10-2

#### Question - 5

Copper of fixed volume V is drawn into wire of length 1. When this wire is subjected to a constant force F, the extension produced in the wire is 111. Which of the following graphs is a straight line?

• A Δl versus 1/l
• B Δl versus l2
• C Δl versus 1/l2
• D Δl versus l

#### Question - 6

The following four wires are made of same material. Which of these will have the largest extension when the same tension is applied?

• A Length = 50 em, diameter = 0.5 mm
• B Length= 100 em, diameter= 1mm
• C Length = 200 em, diameter = 2 mm
• D Length= 300 em, diameter= 3 mm

#### Question - 7

The potential energy of particle in a force field is U=A/r2 - B/r, where A and B are positive constants and r is the distance of particle from the centre of the field. For stable equilibrium, the distance of the particle is :

• A B/2A
• B 2A/B
• C A/B
• D B/A

#### Question - 8

When a weight of 10 kg is suspended from a copper wire of length 3 m and diameter 0.4 mm, its length increases by 2.4 em. If the diameter of the wire is
doubled, then the extension in its length will be :

• A 7.6 cm
• B 7.6 cm
• C 1.2 cm
• D 0.6 cm

#### Question - 9

A force of 6 x 106 Nm-2 is required for breaking a material. The density p of the material is 3 x 103 kg m-3. If the wire is to break under its own weight, the length of the wire made of that material should be (Taking g = 10 ms-2)

• A 20 m
• B 200 m
• C 100 m
• D 2000 m

#### Question - 10

The Young's modulus of brass and steel are respectively 1.0 x 1011 Nm-2 and 2.0 x 1011 Nm-2. A brass wire and a steel wire of the same length are extended by 1 mm each under the same force. If radii of brass and steel wires are RB and Rs respectively, then:

• A ${ R }_{ S }=\sqrt { 2R_{ B } }$
• B ${ R }_{ S }={ R }_{ B }/\sqrt { 2 }$
• C Rs = 4RB
• D Rs = RB/2