The limiting frictional force between two surface depends on

I. the normal reaction between the surfaces

II. the area of surface in contact

III. the relative velocity between the surfaces

IV. the nature of the surface

**A.**I only**B.**I & IV only**C.**II only**D.**III only

**Correct Option: Answer is B**

Friction depends on the nature of the surfaces in contact

– Solid friction is independent of the area of the surfaces in contact and the relative velocity between the surfaces.

**2. **If a body moves with a constant speed and at the same time undergoes an acceleration, its motion is said to be

**A.**oscillation**B.**circular**C.**rotational**D.**rectilinear

**Correct Option: Answer is B**

**3. **When blue and green colours of light are mixed, the resultant colour is

**A.**cyan**B.**magenta**C.**black**D.**yellow

**Correct Option: Answer is A**

Cyan is a bluish-green colour

**4. **A metal rod has a length of 100cm at 200\(^oC\). At what temperature will its length be 99.4cm. If the linear expansivity of the material of the rod is 2 x 10\(^{-5}C^{-1}\)

**A.**200\(^o\)C**B.**300\(^o\)C**C.**100\(^o\)C**D.**-100\(^o\)C

**Correct Option: Answer is D**

L\(_1\) = 100cm, T\(_1\) = 200\(^o\)C

L\(_2\) = 99.4cm,T\(_2\) = ?

\(\alpha\) = 2 x 10\(^{-5}\)C\(^{-1}\)

\(\alpha\) = \(\frac{L_2 – L_1}{L_1(T_2 – T_1)}\)

2 x 10\(^{-5} = \frac{100- 99.4}{100(200 – T_2)} = \frac{0.6}{100(200 – T_2)}\)

2 x 10\(^{-5}\) x \(100(200 – T_2) = 0.6\)

\(200 – T_2 = \frac{0.6}{0.002} = 300^oC\)

\(T_2 = 200 – 300 = -100^oC\)

**5. **According to kinetic molecular model, in gases

**A.**The molecule are very fast apart & occupy all the space made available**A.**The particles vibrate about fixed positions and are held together by the strong intermolecular bond between them**B.**The particles occur in clusters with molecules slightly farther apart**D.**The particles are closely packed together, they occupy minimum space & are usually arranged in a regular pattern

**Correct Option: Answer is A**

In kinetic molecular model, gases are energised and thus moves freely, fast as they occupy specific space

**6. **

The value of T in the figure above is

**A.**30N**B.**10.0N**C.**20N**D.**40N

**Correct Option: Answer is D**

Tsin30 + Tsin30 =40

2Tsin30 = 40

Tsin30 = 40/2 = 20

T(\(\frac{1}{2}\)) = 20

T = 20 x 2 = 40N

**7. **A train has an initial velocity of 44m/s and an acceleration of -4m/s${}^{2}$. Calculate its velocity after 10 seconds

**A.**10m/s**B.**6m/s**C.**8m/s**D.**4m/s

**Correct Option: Answer is D**

**8. **Lamps in domestic lightings are usually in

**A.**series**B.**divergent**C.**convergent**D.**parallel

**Correct Option: Answer is D**

Lamps in lightnings are arranged to reduce the heat losses

– resultant resistance is small for parallel arrangement which indicate low heat losses [Heat $\alpha $ R]

**9. **During the transformation of matter from the solid to the liquid state, the heat supplied does not produce temperature increase because

**A.**all the heat is used to break the bonds holding the molecules of the solid together**B.**the heat capacity has become very large as the substance melts**C.**the heat energy is quickly conducted away**D.**the heat gained is equal to the heat lost by the substance

**Correct Option: Answer is A**

**10. **In a slide wire bridge, the balance is obtained at a point 25cm from one end of wire 1m long. The resistance to be tested is connected to that end and a standard resistance of 3.6\(\Omega\) is connected to the other end of the wire. Determine the value of the unknown resistance

**A.**3.2\(\Omega\)**B.**1.4\(\Omega\)**C.**3.21\(\Omega\)**D.**1.2\(\Omega\)

**Correct Option: Answer is D**

\(\frac{R}{3.6} = \frac{75}{25} = \frac{1}{3}\)

3R = 3.6

R = 1.2\(\Omega\)