Explanation

(a) Projectile is an object thrown into the air, and left to move under the influence of gravity.

(b) the acceleration of free fall due to gravity does not act in the horizontal direction.

Correct Answer: D) 10Ω

Correct Answer: D. 40N

Explanation

(a) Specific latent heat of a substance is the quantity of heat energy required to change a unit mass of a substance from one state to another without change in temperature. The unit specific latent heat is Jkg\(^{-1}\).

(b)(i) Mass of empty calorimeter = M;

Mass of cal. + water = M\(_2\)

Mass of cal. + water + ice = M\(_3\);

Temp. of warm water = \(\theta_1\)

Final temp. when all the is has melted = \(\theta_2\);

Sp. heat capacity of cal = Cc

Sp. heat capacity of water = C\(_w\)

latent heat of ice = L

Mass of water = M\(_2\) - M\(_1\)

Mass of ice = M\(_3\) — M\(_2\)

Heat lost by cal. and water = (m\(_1\)Cc + (M\(_2\) - M\(_1\))C x ( \(\theta_1\) - \(\theta_2\))

Heat gained by ice in melting to water of 0°C = (M\(_3 - M_2\))L

Heat gained by ice water from 0°C = (M\(^3\) - M\(_2\))C\(_ w \theta_2\),

Total heat gained = Heat lost (M\(_3\) - M\(_2\)L + (M\(_3\) - M\(_2\))

C\(_w \theta_2\) = (M\(_1\)Cc + (M\(_2\) - M\(_1\)) C\(_w\) (\(\theta_2 - \theta_2\)

L = \(\frac{M_1C_c + (M_2 - M_1) C_w(\theta_1 - \theta_2) - (M_3 M_2)C_w\theta_2}{(M_3 - M_2)}\)

(ii) Precautions

- Stir gently

- Ensure that ice is dry before adding to water

- Avoid parallax error in reading the balance and thermometer.

(c) If M\(_s\) = mass of steam ; Heat lost by steam at 100°C = M\(_s\)l\(_v\) = M\(_s\) x 2.3 x 10\(^3\)(J)

Heat lost by hot water from 100°C = 0°C ;

= \(M_sC_w \Delta \theta\) = \(M_s\) x 4.2 x 100 (J) Heat gained by ice at 0\(^oC\)

= M\(_{\text{ice}}\) L\(_f\) = 20 x 3.4 x 10\(^2\) = 6800J;

Heat lost by steam + hot water = Heat gained by ice;

M\(_sl_v\) + M\(_s\)C\(_w\)\(\Delta\) = M\(_{\text{ice}}\)L\(_f\);

M\(_s\) (2.3 x 10\(^3\) + 4.2 x 100) = 6800;

M\(_s\) = \(\frac{6800}{2720}\) = 2.5g

Mass of water in container = mass of melted ice + mass of water + mass of condensed steam.

= 20 + 100 + 2.5 = 122.5g

Correct Answer: D. angle of dip

Correct Answer: D. i, ii and iii

Correct Answer: D. 12.00cm

Explanation

\(\frac{\text {object height}}{\text{image height}}\) = \(\frac{\text {object distance}}{\text{image distance}}\)

\(\frac{3}{\text{image height}}\) = \(\frac{10}{40}\)

Image height = 12cm

Correct Answer: D. Dew

Explanation

Matter is made up of molecules which are held together by intermolecular forces which make the molecules to vibrate about their mean positions giving the solids definite shape.

Correct Answer: B. the floating of a dry needle in water

Explanation

A carefully placed small needle can be made to float on the surface of water even though it is several times as dense as water. If the surface is agitated to break up the surface tension, then needle will quickly sink.