(a) Fleming's Left Hand Rule: Stretch the first three fingers of the left hand mutually perpendicular to each other such that the fore-fingers points the direction of magnetic field, the middle finger points the direction of current, then the thumb will indicate the direction of force experienced by the conductor. It is to be applied when the current and field are perpendicular to each other.

(b) Vertically downward or into the plane of the paper.

(b) The degree of closeness of magnetic field lines near the poles signify that the field is stronger there.

When- carboxylic acid reacts with alcohol in the presence of cone. H₂SO₄, pleasant fruity smelling compound, ester is formed. This reaction is called esterification
\(CH_3COOH(l)+C_2H_5OH(l)\)\(\overset { conc. }{ \underset { H2SO4 }{ \leftrightarrows } } \)CH₃COOC₂H₅(l) + H₂O(l)
Ethanoic acid         Ethanol                Ethyl Ethanoate    Water
Activity:
1.Take 1 mL of ethanol in a test tube. Add 1 mL of acetic acid in this test tube.
2. Add few drops of cone. H₂SO₄ in the mixture
3. Heat the content on water bath for 5 minutes.
4. Smell the resulting mixture formed.

(a) CH₃CH₂OH\(\overset { \quad conc.H2SO4 }{ \underset { heat }{ \longrightarrow } } \)  H₂C=CH₂ + H₂O
CH₃COOH + NaHCO₃ \(\longrightarrow \)CH₃COONa + H₂O + CO₂
CH₄ + Cl₂ \(\overset { sunlight }{ \longrightarrow } \)CH₃CI + HCI
(b) (i) Propanoic acid (ii) Bromoethane
(c) Electron dot structure of ethene

(a) Ohm's Law states that at constant temperature, current flowing through a conductor is directly proportional to the       potential difference across its ends.

The magnetic field lines have the following properties
(i) They originate from North pole of a magnet and end at its south pole, by convention.
(ii) These lines are closed and continuous curve.
(iii) Field lines never intersect each other.
(iv) They are crowded near the poles, where the magnetic field is strong and separated far from the poles, where the magnetic field is weak.

The total energy consumed by the refrigerator in 30 days would be 400 W × 8.0 hour/day × 30 days = 96000 W h = 96 kW h
Thus the cost of energy to operate the refrigerator for 30 days is 96 kW h × Rs 3.00 per kW h = Rs 288.00

The formula for cyclopentane is C₅H₁₀. Its electron dot structure is

Soaps are sodium salts of fatty acids. It is biodegradable and shows cleansing action by removing dirt.
Mechanism of cleansing action:
Soap molecule has two ends, the charged end that gets attracted towards water is called hydrophilic and the long carbon chain that repels water is called hydrophobic tail. When soap is dissolved in water, the carbon chain i.e., hydrophobic end gets attracted towards the oil, dirt and grease. The hydrophilic end stays away from this. ' The micelle formation takes place. The tail entangles dirt, oil or grease, if required, the agitation is done. Lot of rinsing is done with water so that water molecules attract charged (Na+) end and carries the soap molecules with dirt attached to it and clean the clothes, utensils, etc:

Scum formation: Hard water often contains salts of calcium and magnesium. Soap molecules react with the salts of calcium and magnesium and form a precipitate. This precipitate begins floating as an off-white layer over water. This layer is called scum. soaps lose their cleansing property in hard water because of formation of scum.
In case of detergents, the salts present in hard water does not react with the molecules of detergent to form insoluble scum, but the molecules of detergent remain as it is and helps in the cleansing action.

\({ R }=\rho \overset { l }{ \underset { A }{ \_ \_ } } \)
\(\overset { \rho }{ \underset { A }{ \_ \_ } } =\overset { R }{ \underset { l }{ \_ \_ } } \)   Constant = K (for same I and R)
\(\rho =kA\)
 \(\rho \propto A\)
So, for different materials having same resistance per unit length, greater resistivity material wire has more cross-sectional area.
(i) Current through each resistor
I_I  =\(\frac { V }{ { R }_{ 1 } } =\frac { 6 }{ 5 } =1.2A\)
I₂ =\(\frac { V }{ { R }_{ 2 } } \frac { 6 }{ 10 } =0.6A\)
I₃ =\(\frac { V }{ { R }_{ 3 } } \frac { 6 }{ 30 } =0.2A\)
Current in 5\(\Omega\), 10\(\Omega\) and 30\(\Omega\) are therefore, 1.2 A, 0.6 A and 0.2 A respectively.
(ii) Total current drawn from the battery
I = I_I + I₂ + I₃ = 1.2 + 0.6 + 0.2 = 2.0 A
(iii) R_l = 5\(\Omega\), R₂ = 10\(\Omega \) nand R₃ = 3\(\Omega \) n are connected in parallel. So their equivalent resistance
\(\frac { 1 }{ R } =\frac { 1 }{ { R }_{ 1 } } +\frac { 1 }{ { R }_{ 2 } } +\frac { 1 }{ { R }_{ 3 } } =\frac { 1 }{ 5 } +\frac { 1 }{ 10 } +\frac { 1 }{ 30 } =\frac { 1 }{ 3 } \)
R =3 \(\Omega \)

(a) Homologous series is series of compounds having same functional group and same chemical properties. ,When members of the series are arranged in ascending order, two successive members differ by -CH₂ group and mass 14 u.
Example: Alcohol
CH₃OH  
C₂H₅OH  \(\longrightarrow\) differ by -CH₂ group and mass 14. a.m.u.
C₃H₇OH
(b) Ethanol reacts with ethanoic acid to produce a fruity smelling compound called ester, the conc. sulphuric acid is used as dehydrating agent which removes water. Such reaction is called esterification.

(c) Hard water contains salts of Ca and Mg. Soap molecule reacts with these salts to produce white precipitate called scums which is insoluble in water and the cleansing action of soap becomes ineffective.

(a) An electromagnet is a device used to produce magnetic field with the help of electricity.
(b) An electromagnet is used for lifting heavy loads. It is also used in automatic door locking systems.
(c)
 
(d) A soft iron is used as a core in order to strengthen the magnetic field created by the electromagnet.

(a) If both assertion and reason are true and the reason is correct explanation of assertion.

(d) If both assertion and reason are false

(i) (a) North-South 
The current flows in the east-west direction. From right hand thumb rule, we get the direction of magnetic field as from north to south. The direction of magnetic field will be same at every point below the power line.
(ii) (c) Both of these
(iii) (a) Upward
The direction of the Earth's magnetic field is from geographic south to north. Let the direction of current in the conductor be from west to east. Applying Fleming's left-hand rule, we find, that the direction of the force acting on the conductor will be vertically upwards,
(iv)  (b) magnetic field lines
The direction of curl of fingers of the right hand gives the direction of magnetic field lines.
(v)  (b) stronger inside the loop than outside the loop
Magnetic field is strongest near the centre of the loop.

(i) (b): In series combination, the total voltage is equal to the sum of voltage drop across each resistance.
(ii) (b): R_s = R₁ + R₂ + R₃
So, R_s = R + R + R = 3R
(iii) (a): Resistance of each wire = 20/4 = 5 \(\begin{equation} \Omega \end{equation}\)
Equivalent resistance in series
R_s = 5 + 5 + 5 + 5 = 20 \(\begin{equation} \Omega \end{equation}\)
(iv) (a): All are in series, R_s = 5R= 5 x 2 = 10\(\begin{equation} \Omega \end{equation}\)
(v) (a): R_s = 1 + 2 + 3 = 6 \(\begin{equation} \Omega \end{equation}\)
\(\begin{equation} I=\frac{18}{6}=3 \mathrm{~A} \end{equation}\)