answer

# Answer of SET 3

**Answer of Set 3**

**1. b**

Vector quantities :Acceleration, Current Density, Dipole moment, Displacement, Electric Field, Force, Impulse, Magnetic Dipole Moment, Momentum, Velocity, Weight, Thrust, etc.

Vector= magnitude + direction

All field strength, gradients of scalar are vector.

e.g. magnetic intensity, velocity gradient, etc.

**2. a**

Scalar quantities: time , volume , speed, mass , temperature , distance, entropy, energy, Temperature, Area, frequency, etc

Scalar= only magnitude no particular direction

All potentials, flux of vectors are scalar.

eg. magnetic flux, gravitational potential, etc

**3. c**

Tensor quantities: Stress, strain, permeability

Tensor= magnitude + direction+ area vector

**4. d**

Dimensionless quantities:

eg. strain, solid angle, coefficient of friction, refractive index, magnification, angle, power factor, phase, reflectance, transmittance, all ratios, etc.

**5. b**

Conduction is the slowest process of heat transfer.

Radiation> Convection> Conduction

**6. d**

total power =power by bulb+ power by rod

=5*200(in watt)*5(in hours)+3*2000(in watt)*3(in hour)

=1000(in watt)*5(in hours)+6000(in watt)*3(in hour)

=5kwh+18kwh (i.e.1000watt=1 kw)

=23 khw=23 unit

**7. c**

Displacement is shortest distance.

apply Pythagoras theorem to find displacement.

velocity=displacement/time

=15/5

=3 m/s

**8. c**

For third class lever MA is always less than 1.

**9. c**

Resistance(R),resistivity(ρ),length of wire(l), volume(v), area(A)

R=ρ*l/A

=ρ*(l*l)/(A*l) (ie multiplying both by l)

=ρ*(l*l)/v

Since ρ and ρ are constant

R∝(l*l)

Now on calculation we get change in resistance is 21% (increases).

**10. b**

From above:

R=ρ*l/A

By multiplying numerator and denominator by A we can find out the change.

Since,

R∝1/(A*A)

on calculation we get change in resistance is 21% (decreases)

**11. b**

Liquid non metal - Bromine

**12. c**

cation<parent atom<anion

Radius of element can be compared by Z/e ratio where

Z= atomic number

e= number of electrons

Smaller the Z/e ratio, larger the atomic size and vice versa.

**13. d**

Eka boron = Scandium

Eka silicon = Germanium

Eka aluminium =Gallium

Eka manganese = Technitium

**14. b**

Nitrogen family- Pnicogens

Oxygen family- Chalcogens

VII A family- Halogens

Inert gases family - Aerogens

**15. a**

Atomic hydrogen is most reactive form of hydrogen.

**16. c**

Spinal reflex : Knee jerk

Cerebral reflexes : sneezing, Eye blinking & salivation.

Both cerebral and spinal reflexes: Hunger & cough

**17. a**

Pneumatic bones are features of Volant adaptation.(eg. Aves)

**18. a**

Functions of hypothalamus - (SEAT)^2

S-Sexual life, sleeping pattern

E- Emotions, Endocrine glands

A-Apetite, Automatic Nervous system

T-Thirst Temperature

**19. c**

Reproductive system of parasite is most developed.

**20. a**

Phototaxis- response to light

Chemotaxis- response to Chemical

Thermotaxis- response to Temperature

Geotaxis- response to Gravity

Rheotaxis - response to Flow of water

Thigmotaxis- response to touch

**Practice set 1- Click here**

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