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(a) angle of projection : q₁ > q₂ 

(b) time of flight : T₁ > T₂

Its range will be,

(c) 100 m 

At the highest point vertical component of velocity becomes zero thus direction of motion of projectile becomes horizontal.  

Three times the initial vertical height. 

Four times the initial horizontal range. 

Acceleration must be perpendicular to the direction of motion and is called centripetal acceleration. 

π/6 radian per hour.  

When an object moves in a circular path with constant speed then the motion is called uniform circular motion 

Time period – The time taken by the object to complete one revolution 

Frequency – The total number of revolutions in one second is called the frequency. 

Angular velocity – It is defined as the time rate of change of angular displacement.

W = 2π/T = 2πv       (1/T = v)

v = 600 revolutions/min

v = 600/60 revolutions/sec.

w = 2πv = 2 x π x 600/60

w = 20π rad/s

(b) A,B are antiparallel

1. If the forces act in opposite directions, the resultant is zero.

2. If the forces act in the same direction, resultant \(\vec R = 2 \vec F.\)

3. For \(\vec R = 2 \vec F\)

\(\sqrt {F^2 +F^2 +2F.F.cos\theta} = F\)

⇒ 2F² (1 + cosθ) = F²

⇒ 1 + cosθ =\(\frac {1}{2}\)

⇒ θ = 120°

It is true. The component of a vector can never have a magnitude greater than the vector itself.

MCQ Questions for Class 11 Physics Motion in a Plane with Answers are set up according to the Latest Exam Pattern. These MCQ Questions for Class 11 Physics with answers clear for a fast revision. Students are encouraged to practice the Class 11 Physics MCQ Questions of Motion in a Plane with Answer is accessible here. 

Motion in a Plane is a very important concept in Physics, which basically describes the change in position of an object over a period of your time. Motion in a Plane will be represented with the assistance of the following terms such as:

• Displacement
• Distance
• Velocity
• Acceleration
• Time
• Speed

You can start practice with MCQ Question for class 11 with Answers for Board Exams.

Practice MCQ Questions for class 11 Physics Chapter-Wise

1. The angular velocity depends upon the rate of change of the?

(a) Angular acceleration
(b) Angular Distance
(c) Angular Displacement
(d) torque

2. A small body attached at the end of an inextensible string completes a vertical circle, then its

(a) angular momentum remains constant
(b) linear momentum remains constant
(c) angular velocity remains constant
(d) total mechanical energy remains constant

3. A body is travelling in a circle at a constant speed. It

(a) has a constant velocity
(b) is not accelerated
(c) has an inward radial acceleration
(d) has an outward radial acceleration

4. When a body P moves on a circular path, the centripetal acceleration is

(a) directed inwards from P, to the centre of the circle
(b) directed tangential to the circumference of the circle, at P
(c) directed perpendicular to the planc of the circle, at P
(d) directed outward, perpendicular to the circumference of the circle

5.  The path followed by a projectile is called its?

(a) Territory
(b) Treasury
(c) Tractor
(d) Trajectory

6. One radian is defined to be the angle subtended where the arc length S is exactly equal to the?

(a) radius of the circle
(b) diameter of the circle
(c) circumference of the circle
(d) half of radius of the circle

7. A car sometimes overturns while taking a turn. When it overturns, it is

(a) the inner wheel which leaves the ground first
(b) either inner wheel or the outer wheel leaves the ground
(c) both the wheel leave the ground simultaneously
(d) the outer wheel which leaves the ground first

8. The centripetal component of acceleration arises when? 

(a) The direction of motion is changed
(b) The direction propagation is changed
(c) The direction of gravity is changed
(d) The direction of projectile is changed

 Answer : (a) The direction of motion is changed

9. The word centripetal is derived from two Greek words meaning?

(a) Seeking the situation
(b) Seeking the centre
(c) Touching the centre
(d) Leaving the centre

10. A body is moving along a circle with an increasing speed. It possesses?

(a) centripetal acceleration only (ac)
(b) tangential acceleration only (ar)
(c) both tangential and centripetal acceleration (a_r and a_c)
(d) No acceleration

11. Which of the following conditions are sufficient and essential for a quantity to be a vector?

(a) Magnitude, direction, and addition, subtraction multiplication and division by vector laws
(b) Magnitude, direction and combination of vectors by ordinary rules of algebra
(c) Magnitude and addition, subtraction, multiplication by ordinary rules of algebra
(d) Magnitude and direction

12. How many minimum number of vectors in different planes can be added to give zero resultant?

(a) 4
(b) 5
(c) 3
(d) 2

13. Acceleration due to gravity

(a) polar vector
(b) a scalar
(c) a vector
(d) None of these

14. The resultant of A × 0 will be equal to

(a) zero vector
(b) zero
(c) A
(d) unit vector

15. For motion in two or three dimensions, the angle between velocity and acceleration is

(a) Any angle between 0° & 180°
(b) 180°
(c) 90° ​​​​​​
(d) 0°

16. Centripetal acceleration is

(a) not a constant vector
(b) a magnitude changing vector
(c) a constant scalar
(d) a constant vector

17. The direction of the angular velocity vector is along

(a) the axis of rotation
(b) the outward radius
(c) the inward radius
(d) the tangent to the circular path

18. Two bullets are fired horizontally and simultaneously towards each other from roof tops of two buildings 100 m apart and of same height of 200m with the same velocity of 25 m/s. When and where will the two bullets collides. (g =10 m/s²)

(a) after 2s at a height 180 m
(b) after 2s at a height of 20 m
(c) after 4s at a height of 120 m
(d) they will not collide

19. A projectile is fired from the surface of the earth with a velocity of 5 m/s and angle θ
with the horizontal. Another projectile fired from another planet with a velocity of 3 m/s at the same angle follows a trajectory, which is identical to the trajectory of the projectile fired from the earth. The value of the acceleration due to gravity on the planet (in m/s²) is: [Given, g = 9.8 m/s²]

(a) 3.5
(b) 5.9
(c) 16.3
(d) 110.8

20. In a uniform circular motion, which of the following quantity is not constant

(a) Angular momentum
(b) Speed
(c) Kinetic energy
(d) Momentum

21. A train is moving towards east and a car is along north, both with same speed. The observed direction of car to the passenger in the train is 

(a) East-north direction
(b) West-north direction
(c) South-east direction
(d) None of these

22. If the body is moving in a circle of radius r with a constant speed v, its angular velocity is:

(a) v²/r
(b) vr
(c) v/r
(d) r/v

23. A particle moves with constant angular velocity in a circle. During the motion its

(a) Energy is conserved
(b) Momentum is conserved
(c) Energy and momentum both are conserved
(d) None of the above is conserved

24.  A bomb is dropped from an aeroplane moving horizontally at constant speed. When air resistance is taken into consideration, the bomb 

(a) Falls to earth exactly below the aeroplane
(b) Fall to earth behind the aeroplane
(c) Falls to earth ahead of the aeroplane
(d) Flies with the aeroplane

25. A particle is moving in a horizontal circle with constant speed. It has constant

(a) Velocity
(b) Acceleration
(c) Kinetic energy
(d) Displacement

Answer:

1. Answer : (c) Angular Displacement

Explanation: The orbital angular velocity vector encodes the time rate of change of angular position, as well as the instantaneous plane of angular displacement.

2. Answer : (d) total mechanical energy remains constant

Explanation: Mass of the system is constant and no word is done by any external force (no force is acting in direction of motion only force acting is tension force which is perpendicular to the velocity of the ball so work done is zero) so mechanical energy of the system is conserved.

3. Answer : (c) has an inward radial acceleration

Explanation: Body moves with constant speed it means that tangential acceleration a_T = 0 & only centripetal acceleration a_C exists whose direction is always towards the centre or inward

4. Answer : (a) directed inwards from P, to the centre of the circle

Explanation: So for an object moving in a circle, there must be an inward force acting upon it in order to cause its inward acceleration. This is sometimes called as centripetal force.

5. Answer : (d) Trajectory

Explanation: The path followed by a projectile is called its trajectory.

6. Answer : (a) radius of the circle

Explanation: One radian is defined as the angle subtended from the center of a circle which intercepts an arc equal in length to the radius of the circle.

7. Answer : (a) the inner wheel which leaves the ground first

Explanation: The inner wheel which leaves the ground first. Because the reaction on inner wheel decreases and becomes zero.

8. Answer : (a) The direction of motion is changed

Explanation: The acceleration of a body traversing a circular path. Because velocity is a vector quantity (that is, it has both a magnitude, the speed, and a direction), when a body travels on a circular path, its direction constantly changes and thus its velocity changes, producing an acceleration.

9. Answer : (b) Seeking the centre

Explanation: The word'centripetal'is derived from two Latin words 'centrum 'and 'petus' that translate into'center'and'seeking. 'Thus, centripetal acceleration is instantaneous acceleration that 'seeks the center' of the circle, or is directed toward the center of the circle.

10. Answer : (c) both tangential and centripetal acceleration (a_r and a_c)

Explanation: If a body is moving with increasing velocity on a circular path, it possesses both tangential and centripetal acceleration. If velocity is constant, it possesses centripetal acceleration.

11. Answer : (a) Magnitude, direction, and addition, subtraction multiplication and division by vector laws

Explanation: A vector quantity is defined as the quantity which has magnitude and direction and for which all the mathematical operations are possible only through vector laws.

12. Answer : (a) 4

Explanation: If the vectors are in different planes, they would need to cancel components in at least 3 dimensions to make the resultant 0. Hence, we would need at least 4 vectors such that 3 of them when added cancel their components in a plane and add to get a single vector perpendicular to this plane.

13. Answer : (a) polar vector

Explanation: Acceleration is the rate at which the velocity of a body changes with time. It has both magnitude and direction but its direction is not decided by its rotation about any axis like non polar vectors (axial), hence it is a polar vector.

14. Answer : (a) zero vector

Explanation: The cross product  vector A x B it a vector, with its direction perpendicular to both vector A and B. A x B is area. If side B is zero, area is zero. vector A x 0 is a zero vector.

If in case 0 is a scalar, then also the product is zero. But a scalar x a vector is also a vector. Hence one gets a zero vector in any case.

15. Answer : (a) Any angle between 0° & 180° 

Explanation: For motion of two or three dimension, the angle between velocity and acceleration vector should be between 0 and 180 degree. If the angle is 0 degree then the body will move in only one direction.

16. Answer : (a) not a constant vector

Explanation: A magnitude changing vector. Since velocity and radius are constants for a given uniform circular motion, so the magnitude of centripetal acceleration is also always constant. But, the direction of centripetal acceleration changes continuously in the circular path.

17. Answer : (a) the axis of rotation

Explanation: \(v=r\times\omega\)

v is the tangential. If r is in the XY plane and v is also in this plane,w is in the Z direction. + or − is decided by whether the particle is rotating in the anticlockwise direction or clockwise direction.

18. Answer : (a) after 2s at a height 180 m

Explanation: t = d/v_rel

= 100/50

= 2s

s_y = −1/2gt² 

= -1/2 x 10 x 4

= -20

∴ H = 180m

19. Answer : (a) 3.5

Explanation: For same trajectory both should have same horizontal range and maximum heights

⇒ 5²/g = 3²/a

⇒ a = 9.8 x 9/25

= 3.5

20. Answer : (d) Momentum

Explanation: The linear momentum doesn't remain constant as momentum is mass x velocity and the direction of velocity keeps on changing. Whereas mass, speed and kinetic energy remain constant over the uniform circular motion

21. Answer : (b) West-north direction

Explanation: For a passenger in the train, the car has one velocity component in the north direction due to its absolute motion and another velocity component in the west direction due to relative motion with respect to the passenger (since the train is moving along east).

tanθ = (-v/v)

θ = 135°

22. Answer : (c) v/r

Explanation: v = rω

∴ω =v/r = constant [As v and r are constant]

23. Answer : (a) Energy is conserved

Explanation: KE \(\propto\) v²

P = mv . In uniform circular motion (constant angular velocity) kinetic energy remains constant but due to change in velocity of particle its momentum varies.

24. Answer : (b) 

Explanation: If there is no resistance, bomb will drop at a place exactly below the flying aeroplane. But when we take into account air resistance, bomb will face decceleration in its velocity. So it will fall on the earth exactly behind aeroplane.

25. Answer : (c) 

Explanation: If an object is moving in a horizontal circle at constant speed, the centripetal force does not do work and cannot alter the total mechanical energy of the object. For this reason, the kinetic energy and therefore, the speed of the object will remain constant. 

Click here to practice MCQ Questions for Motion in a Plane class 11

For maximum resultant

P + Q=17N ........... (1)

For minimum resultant

P - Q = 7N .............. (2)

Eq(1) + (2) gives 2P = 24 Or P = \(\frac {24}{2}\) = 12N.

From (1), Q = 17 - 12 = 5N

When P and Q are in perpendicular directions,

R = \(\sqrt {P^2+O^2}\)

= \(\sqrt {12^5+5^2}\)

= 13N

(∵ cos 90° = 0).

Given, P = Q & R² = 3PQ = 3P²

we have R² = P² + Q² + 2PQ cosθ

i.e. 3P²= P² + P² + 2P² cosθ

i.e. 3P² = 2P² + 2P² cosθ

1P² = 2P² cos θ

\(\frac{1}{2}\)= cose

⇒ θ = cos^-1 \((\frac{1}{2})\) = 60°

No, because a vector along X-axis has no component in Y- and Z-axis. So, it has a non-zero value.

180° Clearly, the given vectors act in opposite directions.

Consider two vectors A and B such that the angle between them is θ.

The component of the vector A along the direction of vector B is A cosθ.

Since A  cosθ = 0. It is possible if θ = 90°, because cos = 90° = 0.

Thus, vector A and B are perpendicular to each other.

Scalar quantities: Work, current.

Anybody was thrown into space, that moves under the effect of gravity is called a projectile. 

E.g.:

• A bullet fired from the gun. 
• A javelin thrown by an athlete.

No, because vector of only same type and nature can be added vectorially, e.g., velocity cannot be added to force.

The resultant of two equal and opposite vectors is zero vector.

Motion of a particle in a plane is known as two-dimensional motion. 

Example:

• A car moving along a zig-zag path on a road. 
• Motion of the planet around the sun in its orbit.

Scalar: Volume, mass, speed, density, number of moles, angular frequency. 

Vector: Acceleration, velocity, displacement, angular velocity.

A vector physical quantity must obey the commutative law of vector addition. So, the given quantity should be checked on this account.

k is the unit vector perpendicular to vector A.

= \(\sqrt {a^2+b^2+c^2} =1\)

⇒\(\sqrt {0.6^2 +0.8^2 +c^2} =1\)

⇒ \(\sqrt{1+c^2} =1\)

\({c =0}\).

Yes, unit of a vector multiplied by a dimensionless scalar do change, e.g., velocity (ms^-1) multiplied by mass (kg) gives momentum (kgms^-1 ).

Volume of water striking the wall per second = v x A

= 15 x 10^-2 = 0.15 m^-3 s^-1

Mass of water hitting wall per second

= 9 x v x A

= 1000 x 0.15 kg s^-1 = 150 kg s^-1

Initial momentum of water per second

= 150 x 150 = 2250 kg ms^-1

Final momentum of water per second = 0 (There is no rebound of water)

Magnitude of force = Rate of change of momentum

= 2250 N

The volume of water hitting the wall per second

= (Area × Velocity) of a stream of water

= 10^-2 × 15

= 0.15 m³s^-1

density of water = 1000 kg/m³

∴ mass of water hitting the wall per second

= 0.15 × 1000= 150 kg/s

Initial momentum of water hitting the wall per second

= 150 × 15

= 250 kg m/s² or 2250 N

Final momentum per second = 0 

∴ Force exerted on the wall: change in momentum per second 

= 2250 N.

We have

\(\vec A.\vec B\)= | A | | B | cos θ

Here  | A | = \(\sqrt{1^2+1^2+(-2)^2}=\sqrt6\)

| B | =\(\sqrt{1^2+1^2+(-1)^2}=\sqrt3\)

\(\vec A.\vec B=(\hat i+\hat j-\hat k).(\hat i+\hat j-\hat k)\)

= 1 × 1 + 1 × 1 + (-2)(-1)

= 1 + 1 + 2 = 4 

∴   cos θ = \(\frac{\vec A.\vec B}{|A||B|}=\frac{4}{\sqrt6\sqrt3}\)

cos θ = \(\frac{4}{\sqrt{18}}\)

AB = | A | | B | cos θ

∴ cos θ = \(\frac{A.B}{|A||B|}\)

A.B= ( i+ 2j –u ).(−4i +j - 2u)

⇒ (−4 + 2 + 2) = −4 + 4 = 0

cos θ = 0

θ = cos^-1 0

Hence, θ = 90º.

\(M_1=2g,\, \vec r_1=3\hat i+2\hat j -u\)

\(M_2=10g,\, \vec r=3\hat i -\hat j+3u\)

Position vector of centre of mass = \(\frac{M_1r_1+M_2r_2}{M_1+M_2}\)

= \(\frac{2(3i+2j-u)+10(3i-j+3u)}{10+2}\)= \(3i-\frac{1}{2}j+\frac{7}{3}u\)

(d) A scalar quantity has the same value for observers with different orientations of the axes.

The angle between A = cap i+ cap j and B = cap i - cap j is - (b) 90°

(a) F - (500 ×10) = (500 × 15) or F = 12.5 × 10³ N, where F is the upward reaction of the floor and is equal to the force downwards on the floor, by Newton’s 3rd law of motion

(b) R - (2500 × 10) = (2500 × 15) or R = 6.25 × 104 N, action of the air on the system, upwards. The action of the rotor on the surrounding air is 6.25 × 10⁴ N downwards.

(c) Force on the helicopter due to the air = 6.25 × 10⁴ N upwards

Thomson proposed the model of an atom to be similar to that of a Christmas
pudding. The electrons in a sphere of positive charge, where like currants (dry fruits) in a spherical Christmas pudding.

Thomson proposed that: -

i. An atom consists of a sphere of positive charge with negatively charged electrons
embedded in it.

ii. The positive and the negative charges in an atom are equal in magnitude due to
which an atom as a whole is electrically neutral.

Hence, the statements i, ii, iii are correct and the correct option is A.

Correct Answer is: A. 1, 2 Ethylene diamine 

1,2 ethylene diamineis the chelating ligand.

A. 1, 2 Ethylene diamine

Any ion that has partially filled d-orbitals is coloured due to d-d transition in visible light. Ti³⁺(d¹),V³⁺(d²) Mn²⁺(d⁵),Co²⁺(d⁸) are coloured. MnO^4- has purpule colour due to charge-transfer. Cu⁺(d¹⁰) and Sc³⁺(d⁰) are white since there is no d-d transition.

The electronic configurations play a very crucial role in deciding the stability of oxidation states. The presence or absence of complete or half filled d orbitals in that oxidation state decides its stability. Also the ability to give away e^- decide the oxidation state which depends on the energy possessed by it and hence forth its electronic configuration, 

For example Sc shows +3 oxidation state only [M] 3d¹ 4s²⁺1, +2 very unstable due to presence of 1d e^- +3 oxidation state is stable with noble gas configuration. 

Mn : [Ar] 3d⁵ 4s² has +2, +3, +4, +5, +6, +7 states but only +2 and +7 states are stable due to the half filled d orbital or completely empty d orbital. 

similarly Ti = +2, +3, +4 with +4 most stable due to the same reason.

(d) They play an important role in disgestion

Correct Answer is: (c) Thymus

A pair of adrenal glands are located at the anterior end of the kidneys, hence also called suprarenal glands. Anatomically the outer region is the cortex and the inner region is the medulla.

Histologically the adrenal cortex has three distinct zones, zona glomerulosa, zona fasciculata and zona reticularis. Zona glomerulosa an outer thin layer constitutes about 15% of adrenal cortex, and secretes mineralocorticoids.

Zona fasciculata, the middle widest layer constitutes about 75% of adrenal cortex and secretes glucocorticoids such as cortisol, corticosterone and trace amounts of adrenal androgen and oestrogen. Zona reticularis, an inner zone of adrenal cortex constitute about 10% of adrenal cortex and secretes the adrenal androgen, trace amount of oestrogen and glucocorticoids.

Adrenal medulla: It is the central part of adrenal gland and is composed of ovoid and columnar cells, which are found around the network of blood capillaries. Adrenalin (epinephrine) and nor adrenalin (nor epinephrine) are the two hormones secreted by the adrenal medulla. Both adrenalin and nor adrenalin are catecholamines.

Function of adrenal hormones: Glucocorticoids stimulate gluconeogenesis, lipolysis and proteolysis (the life saving avtivity). Cortisol is a glucocorticoid invloved in maintaining cardio vascular and kidney functions.

It produces anti-inflammatory reactions and suppresses the immune response. It stimulates the RBC production. It is also known as stress combat hormone. Mineralocorticoids regulates water and electrolyte balance of our body.

Aldosterone stimulates the reabsorption of sodium and water and eliminates potassium and phosphate ions through excretion,, thus it helps in maintainting electrolytes, osmotic pressure and blood pressure. Adrenal androgen plays a role in hair growth in the axial region, pubis and face during puberty.

The adrenal medulla secretes the hormones adrenalin and noradrenalin and are referred as “3F hormone” (fight, flight and fright hormone). Adrenalin increases liver glycogen breakdown into glucose and increases the release of fatty acids from fat cells.

During emergency it increases heart beat rate and blood pressure. It stimulates the smooth muscles of cutaneous and visceral arteries to decrease blood flow. It increases blood flow to the skeletal muscles therby increases the metabolic rate of skeletal muscles, cardiac muscles and nervous tissue.

A pair of adrenal glands are located at the anterior end of the kidneys. Elence, they are called suprarenal glands.The outer region is called cortex and the inner region is medulla. 

The adrenal cortex has three distinct zones:

1. Zona Glomerulosa 

2. Zona fasciculata 

3. Zona reticularis

1. Zona Glomerulosa: 

• It is the outer thin layer. It constitutes about 15% of the cortex. 
• It secretes mineralocorticoids.

2. Zona fasciculata:

• It is the middle wide layer constituting about 15% of adrenal cortex.
• It secretes glucocorticoids such as cortisol, corticosterone and trace amounts of adrenal androgen and oestrogen.

3. Zona reticularis:

• It is the inner zone of adrenal cortex.
• It constitutes about 10% of adrenal cortex.
• It constitutes about 10% of adrenal cortex.
• It secretes the adrenal androgen, trace amount of oestrogen and glucocorticoids.

The hormones secreted by adrenal cortex are : 

(a) Mineralocorticoids, (b) Glucocorticoids, (c) Gonadocorticoids.

Adrenal cortex secretes 3 types of corticoids – mineralocorticoids, glucocorticoids and sex corticoids. 

I. Mineralocorticoids:

1. The mineralocorticoids regulate ionic and osmotic balance, by regulating the amounts of electrolyte and water. 

2. Aldosterone is the main mineralocorticoid that acts on the renal tubules. 

3. Aldosterone stimulates the re-absorption of Na⁺ and water and excretion of K and phosphate ions. 

4. The aldosterone helps in the maintenance of electrolytes, body fluid volume, osmotic pressure and blood pressure.

II. Glucocorticoids:

1. Cortisol is the main glucocorticoid. Cortisol stimulates many metabolic reactions such as gluconeogenesis, lipolysis and proteinolysis. 

2. It inhibits cellular uptake and utilization of amino acids. 

3. Cortisol also plays an important role in maintaining the cardiovascular system and kidney functions. 

4. It is also involved in anti-inflammatory reactions and suppresses the immune response. 

5. Cortisol stimulates the RBC production.

III. Sex corticoids (Gonadocorticoids).

1. Sex corticoids, Androgens and estradiols are produced by the adrenal cortex. 

2. In males, they have a role in development and maintenance of external sex characters. 

3. Excess sex corticoids in female causes adrenal virilism and hirsutism (excess hair on face) 

4. Excess sex corticoids in males causes gynaecomastia i.e. enlarged breast.

1. The adrenal cortex secretes corticoids. Corticoids is a group of several hormones that control several vital body functions. 

2. Corticoids are of two types, viz. mineralocorticoids and glucocorticoids. 

3. Small amounts of androgenic steroids are also secreted by the adrenal cortex which have the role in the growth of axial and pubic hairs and facial hairs during puberty. 

4. The mineralocorticoids regulate the electrolyte balance while the glucocorticoids are involved in carbohydrate metabolism. 

5. Adrenal medulla secretes adrenaline or epinephrine and noradrenaline or norepinephrine.

Kidney has endocrine tissues which act as partial endocrine gland. It secretes renin, erythropoietin and calcitripl. Renin is secreted by juxta glomerular cells. It increases blood pressure when angiotensin is formed in blood.

Erythropoietin is also secreted by the juxta glomerular cells of the kidney and stimulates erythropoieis in bone marrow. Calcitriol is secreted by proximal tubes of nephrons. It is an active form of vitamin D3 which promotes calcium and phosphorus absorption from intestine and accelerates bone formation.