A retaining wall with vertical back retains a mass of cohesion-less soil, surface of which is level with top of the wall. Active lateral earth pressure coefficient (in terms of 'ϕ') i.e. angle of internal friction of backfill is given by:

\(\dfrac{1+\sin \phi}{1 - \sin \phi} \ \text{or} \ \tan^2 \left(45^\circ - \dfrac{\phi}{2}\right)\)

\(\dfrac{1-\sin \phi}{1 + \sin \phi} \ \text{or} \ \tan^2 \left(45^\circ + \dfrac{\phi}{2}\right)\)

\(\dfrac{1-\sin \phi}{1 + \sin \phi} \ \text{or} \ \tan^2 \left(45^\circ - \dfrac{\phi}{2}\right)\)

\(\dfrac{1+\sin \phi}{1 - \sin \phi} \ \text{or} \ \tan^2 \left(45^\circ - \dfrac{\phi}{2}\right)\)

\(\dfrac{1+\sin \phi}{1 - \sin \phi} \ \text{or} \ \tan^2 \left(45^\circ + \dfrac{\phi}{2}\right)\)

If the lateral pressure on a retaining wall is high, the following measure are taken while designing:

Wall thickness is increased to resist the moment at base

Slab thickness is increased to resist the moment

Height of the retaining wall to be increased to increase the moment resisting capacity

Shear key is provided to resist the lateral pressure

A retaining wall of height H with smooth vertical backface supports a backfill inclined at an angle β with the horizontal. The backfill consists of cohesionless soil having an angle of internal friction ϕ. If the active lateral thrust acting on the wall is Pa, which one of the following statements is TRUE?

Pa acts at a height H/3 from the base of the wall and at an angle ϕ with the horizontal

Pa acts at a height H/3 from the base of the wall and at an angle β with the horizontal

Pa acts at a height H/3 from the base of the wall and at an angle ϕ with the horizontal

Pa acts at a height H/2 from the base of the wall and at an angle β with the horizontal

Pa acts at a height H/2 from the base of the wall and at an angle ϕ with the horizontal

Due to excessive pressure of the retained soil, the retaining wall tend to move:

At its own position i.e. vibration

For cohesion less soil particles, the neutral pressure coefficient of soil is taken as:

\(\dfrac{1- cos\theta}{1 + cos \theta }\)

\(\dfrac{1+sin\theta}{1 -sin \theta }\)

\(\dfrac{1- cos\theta}{1 + cos \theta }\)

\(\dfrac{1-sin\theta}{1 +sin \theta }\)

\(\dfrac{1+ cos\theta}{1 -cos \theta }\)

If top of earth retained is horizontal, the coefficient of passive earth pressure for retaining wall become:

\(\frac{{\sin \left( \phi \right)}\ -\ 1}{{\sin \left( \phi \right)}\ +\ 1} \)

\(\frac{{1 - \sin \left( \phi \right)}}{{1 + \sin \left( \phi \right)}} \)

\( \frac{{1 + \sin \left( \phi \right)}}{{1 - \sin \left( \phi \right)}}\)

\(\frac{{\sin \left( \phi \right)}\ -\ 1}{{\sin \left( \phi \right)}\ +\ 1} \)

\(\frac{{\sin \left( \phi \right)}\ +\ 1}{{\sin \left( \phi \right)}\ -\ 1} \)

Which one of the following is the correct sequence of the given continents in the decreasing order of their percentage of Earth's land?

orth America – Africa – Europe – South America

orth America – Africa – South America – Europe

frica – North America – South America – Europe

orth America – Africa – Europe – South America

frica – North America – Europe – South America

The axis of rotation of earth is tilted by 23.5° to the plane of revolution around the sun. The latitude of Mumbai is less than 23.5° whereas the latitude of Delhi is more than 23.5°. Which one of the following statements in this regard is correct?

t Delhi the sun can come overhead but it will never do so at Mumbai

he sun can come overhead at both these places

he sun will never come overhead at either of these places

t Mumbai the sun can come overhead, but it will never do so at Delhi

t Delhi the sun can come overhead but it will never do so at Mumbai

The location of a place A is at 60° E longitude and 30° S latitude while the location of B is at 60° E longitude and 45° N latitude. Time at B will be ________

alf an hour ahead or behind that of A

The Contour line is those imaginary line which show?

reas of similar atmospheric pressure

Tides are complied and they vary from place to place because of ________

he movement of Moon in relation to Earth

neven distribution of water over the globe

rregularities in the configuration of oceans

Solar eclipse occurs when ________

un comes between moon and earth

arth comes between sun and moon

oon is at right angle to the earth

oon comes between sun and earth

un comes between moon and earth

Sea tides show variations because of ________

ariations in gravitational pull of the moon

ariations in gravitational pull of the sun

istorted spherical shape of the earth

409 + Mcqs in Earth in Geography Page 1 McqOptions

1.	For a sandy soil having an angle of internal friction 30°, the ratio of passive and active lateral earth pressure will be
A.	2
B.	4
C.	3
D.	9
Answer» E.

Discussion

2.	A 6 m high retaining wall having a smooth vertical back face retains a layered horizontal backfill. Top 3 m thick layer of the backfill is sand having an angle of internal friction, ϕ = 30° while the bottom layer is 3 m thick clay with cohesion, C = 20 kPa. Assume unit weight for both sand and clay as 18 kN/m3. The total active earth pressure per unit length of the wall (in kN/m) is:
A.	150
B.	216
C.	156
D.	196
Answer» B. 216

Discussion

3.	A retaining wall with vertical back retains a mass of cohesion-less soil, surface of which is level with top of the wall. Active lateral earth pressure coefficient (in terms of 'ϕ') i.e. angle of internal friction of backfill is given by:
A.	\(\dfrac{1-\sin \phi}{1 + \sin \phi} \ \text{or} \ \tan^2 \left(45^\circ + \dfrac{\phi}{2}\right)\)
B.	\(\dfrac{1-\sin \phi}{1 + \sin \phi} \ \text{or} \ \tan^2 \left(45^\circ - \dfrac{\phi}{2}\right)\)
C.	\(\dfrac{1+\sin \phi}{1 - \sin \phi} \ \text{or} \ \tan^2 \left(45^\circ - \dfrac{\phi}{2}\right)\)
D.	\(\dfrac{1+\sin \phi}{1 - \sin \phi} \ \text{or} \ \tan^2 \left(45^\circ + \dfrac{\phi}{2}\right)\)
Answer» C. \(\dfrac{1+\sin \phi}{1 - \sin \phi} \ \text{or} \ \tan^2 \left(45^\circ - \dfrac{\phi}{2}\right)\)

Discussion

4.	A 6 m high retaining wall with a vertical back has a backfill of silty sand with a slope of 10° for the backfill. With values of KH = 760 kg/m2/m and KV = 100 kg/m2/m, the total active earth pressure will approximately be
A.	128 kN/m
B.	134 kN/m
C.	138 kN/m
D.	142 kN/m
Answer» D. 142 kN/m

Discussion

5.	A retaining wall retains a sand strata with ϕ = 30° up to its top. If a uniform surcharge of 12 t/m2 is subsequently put one the sand strata, then the increase in the lateral earth pressure intensity on the retaining wall will be
A.	1 t/m2
B.	2 t/m2
C.	4 t/m2
D.	8 t/m2
Answer» D. 8 t/m2

Discussion

6.	A homogeneous gravity retaining wall supporting a cohesionless backfill is shown in the figure. The lateral active earth pressure at the bottom of the wall is 40 kPa. The minimum weight of the wall (expressed in kN per m length) required to prevent it fromoverturning about its toe (Point P) is
A.	120
B.	180
C.	240
D.	360
Answer» B. 180

Discussion

7.	In the design of the retaining wall, both, active earth pressure and passive earth pressure are considered due to soil available on both sides (with different heights) of the R. C. C retaining wall. If the angle of repose, ϕ = 30°, then what will be the relation between the coefficient of active earth pressure (Ka ) and passive earth pressure (Kp )
A.	Ka = 1/3 KP
B.	Ka = 3 KP
C.	Ka = 9KP
D.	Ka = 1/9 KP
Answer» E.

Discussion

8.	An earth-retaining structure may be subjected to the following lateral earth pressures:1. Earth pressure at rest;2. Passive earth pressure;3. Active earth pressure.The correct sequence of the increasing order of magnitudes of these pressures is
A.	3, 2, 1
B.	1, 3, 2
C.	1, 2, 3
D.	3, 1, 2
Answer» E.

Discussion

9.	How much increase in pressure will be, if a uniform surcharge of 120 kN/m2 is placed on the back fill with Φ = 30°
A.	12 kN/m2
B.	120 kN/m2
C.	30 kN/m2
D.	40 kN/m2
Answer» E.

Discussion

10.	If the lateral pressure on a retaining wall is high, the following measure are taken while designing:
A.	Wall thickness is increased to resist the moment at base
B.	Slab thickness is increased to resist the moment
C.	Height of the retaining wall to be increased to increase the moment resisting capacity
D.	Shear key is provided to resist the lateral pressure
Answer» E.

Discussion

11.	Consider the following assumptions regarding Coulomb’s Wedge Theory:1) There is an equilibrium of every element within the soil mass of the material2) There is an equilibrium of the whole of the material3) Backfill is wet, cohesive, and ideally elastic4) The wall surface is roughWhich of the above assumptions are correct?
A.	1 and 3 only
B.	1 and 4 only
C.	2 and 3 only
D.	2 and 4 only
Answer» E.

Discussion

12.	According to the level of pressure applied, lateral earth pressure is classified into various types. Which of the following type of lateral earth pressure refers to the minimum pressure exerted by the soil on the retaining wall?
A.	Earth pressure at rest
B.	Active earth pressure
C.	Passive earth pressure
D.	Cylindrical earth pressure
Answer» C. Passive earth pressure

Discussion

13.	A retaining wall of height H with smooth vertical backface supports a backfill inclined at an angle β with the horizontal. The backfill consists of cohesionless soil having an angle of internal friction ϕ. If the active lateral thrust acting on the wall is Pa, which one of the following statements is TRUE?
A.	Pa acts at a height H/3 from the base of the wall and at an angle β with the horizontal
B.	Pa acts at a height H/3 from the base of the wall and at an angle ϕ with the horizontal
C.	Pa acts at a height H/2 from the base of the wall and at an angle β with the horizontal
D.	Pa acts at a height H/2 from the base of the wall and at an angle ϕ with the horizontal
Answer» B. Pa acts at a height H/3 from the base of the wall and at an angle ϕ with the horizontal

Discussion

14.	Due to excessive pressure of the retained soil, the retaining wall tend to move:
A.	Away from the backfill
B.	Towards the backfill
C.	Nowhere
D.	At its own position i.e. vibration
Answer» B. Towards the backfill

Discussion

15.	For cohesion less soil particles, the neutral pressure coefficient of soil is taken as:
A.	\(\dfrac{1+sin\theta}{1 -sin \theta }\)
B.	\(\dfrac{1- cos\theta}{1 + cos \theta }\)
C.	\(\dfrac{1-sin\theta}{1 +sin \theta }\)
D.	\(\dfrac{1+ cos\theta}{1 -cos \theta }\)
Answer» B. \(\dfrac{1- cos\theta}{1 + cos \theta }\)

Discussion

16.	Given that for a soil depositK0 = earth pressure coefficient at restKa = active earth pressure coefficient Kp = passive earth pressure coefficientμ = Poisson’s ratioThe value of (1 - μ )/ μ is given by
A.	K0
B.	Ka / Kp
C.	Kp / Ka
D.	1/K0
Answer» E.

Discussion

17.	A wall 6 m high has a smooth vertical back and retained sand as a backfill that is submerged. The sand has Ysat = 20 kN/m3 and ϕ = 30º. The total active earth pressure is
A.	90 kN/m
B.	60 kN/m
C.	120 kN/m
D.	None of the above
Answer» E.

Discussion

18.	If top of earth retained is horizontal, the coefficient of passive earth pressure for retaining wall become:
A.	\(\frac{{1 - \sin \left( \phi \right)}}{{1 + \sin \left( \phi \right)}} \)
B.	\( \frac{{1 + \sin \left( \phi \right)}}{{1 - \sin \left( \phi \right)}}\)
C.	\(\frac{{\sin \left( \phi \right)}\ -\ 1}{{\sin \left( \phi \right)}\ +\ 1} \)
D.	\(\frac{{\sin \left( \phi \right)}\ +\ 1}{{\sin \left( \phi \right)}\ -\ 1} \)
Answer» C. \(\frac{{\sin \left( \phi \right)}\ -\ 1}{{\sin \left( \phi \right)}\ +\ 1} \)

Discussion

19.	In a certain sea shore, the height of a retaining wall with smooth vertical back is 4.4 m. The foundation is over an expansive collapsible soil and has a horizontal surface at the level of the top of the wall and carries a udl of 197 kPa. The unit weight and angle of internal friction are 19 kN/m3and 30°, respectively. What is the nearest magnitude of the total active pressure per metre length of this sea shore wall?
A.	270 kN/m
B.	360 kN/m
C.	450 kN/m
D.	640 kN/m
Answer» C. 450 kN/m

Discussion

20.	Poisson's ratio of a soil sample is 0.4. Using theory of elasticity, the estimated value of the coefficient of lateral earth pressure at rest in the same soil is:
A.	0.5
B.	0.7
C.	0.3
D.	1
Answer» C. 0.3

Discussion

21.	An excavation is to be made in a saturated soft clay (ϕu = 0) with vertical sides. What will be the maximum unsupported depth of the vertical cut?Given that cohesion intercept = 30 kN/m2, unit weight of clay = 15 kN/m3
A.	5 m
B.	8 m
C.	6 m
D.	4 m
Answer» C. 6 m

Discussion

22.	What is the approximate equatorial circumference of the earth?
A.	0,000 Km
B.	5,000 Km
C.	0,000 Km
D.	5,000 Km
Answer» D. 5,000 Km

Discussion

23.	Which one of the following is the correct sequence of the given continents in the decreasing order of their percentage of Earth's land?
A.	orth America – Africa – South America – Europe
B.	frica – North America – South America – Europe
C.	orth America – Africa – Europe – South America
D.	frica – North America – Europe – South America
Answer» C. orth America – Africa – Europe – South America

Discussion

24.	Owing to the equatorial bulge and the polar flattening, the polar radius of the earth falls short of the equatorial radius by about ________
A.	2 km
B.	6 km
C.	1 km
D.	3 km
Answer» B. 6 km

Discussion

25.	Which of the following countries are located on the Greenwich Meridian?1. Algeria2. Germany3. Guinea4. Iceland
A.	only
B.	only
C.	, 2 and 3
D.	, 3 and 4
Answer» C. , 2 and 3

Discussion

26.	The place which has the longest day and the shortest night on 22nd December, is ________
A.	hennai
B.	adrid
C.	elbourne
D.	oscow
Answer» D. oscow

Discussion

27.	The distance between two consecutive longitudes (91° E and 92° E) at the Poles is
A.	km
B.	8 km
C.	5 km
D.	11 km
Answer» B. 8 km

Discussion

28.	The point below the surface where an earthquake originates is called ________.
A.	sunamis
B.	ocus
C.	picentre
D.	ye of the Earthquake
Answer» C. picentre

Discussion

29.	The axis of rotation of earth is tilted by 23.5° to the plane of revolution around the sun. The latitude of Mumbai is less than 23.5° whereas the latitude of Delhi is more than 23.5°. Which one of the following statements in this regard is correct?
A.	he sun can come overhead at both these places
B.	he sun will never come overhead at either of these places
C.	t Mumbai the sun can come overhead, but it will never do so at Delhi
D.	t Delhi the sun can come overhead but it will never do so at Mumbai
Answer» D. t Delhi the sun can come overhead but it will never do so at Mumbai

Discussion

30.	The deflection of the winds to the right in the northern hemisphere is caused by
A.	evolution of the Earth
B.	otation of the Earth
C.	neven heating of the Earth
D.	ll the above
Answer» C. neven heating of the Earth

Discussion

31.	The position of the earth in its orbit, when it is at its greatest distance from the Sun causing summer in the Northern hemisphere is ________
A.	erihelion
B.	phelion
C.	erigee
D.	pogee
Answer» C. erigee

Discussion

32.	When does tides rise in sea?
A.	nly on lunar day
B.	ull Moon and half Moon
C.	hen Moon is on first phase
D.	nly half Moon
Answer» C. hen Moon is on first phase

Discussion

33.	The location of a place A is at 60° E longitude and 30° S latitude while the location of B is at 60° E longitude and 45° N latitude. Time at B will be ________
A.	alf an hour behind A
B.	alf an hour ahead of A
C.	alf an hour ahead or behind that of A
D.	he same as that of A
Answer» E.

Discussion

34.	The Contour line is those imaginary line which show?
A.	reas of similar atmospheric pressure
B.	reas of similar temperature
C.	reas of similar height
D.	qual Sunning areas
Answer» D. qual Sunning areas

Discussion

35.	Low tides are
A.	trong
B.	eak
C.	oderate
D.	ery Weak
Answer» C. oderate

Discussion

36.	After Sun, which is the closest star to the Earth?
A.	ega
B.	irius
C.	roxima centauri
D.	lpha centauri
Answer» D. lpha centauri

Discussion

37.	If it is 4 P.M. on Monday at 150°W, what will be the time at 150°E ?
A.	a.m. on Tuesday
B.	p.m. on Tuesday
C.	p.m. on Sunday
D.	2 Noon on Tuesday
Answer» E.

Discussion

38.	Lunar eclipse occurs on ________
A.	ew moon
B.	ull moon
C.	alf moon
D.	uarter moon
Answer» C. alf moon

Discussion

39.	Which among the following imaginary line lies at 0° latitude?
A.	quator
B.	ropic of Cancer
C.	ropic of Capricorn
D.	rime Meridian
Answer» B. ropic of Cancer

Discussion

40.	Which of the followings are related with "Lithosphere"?
A.	lant and Insect
B.	arth's Interior
C.	arth's Crust
D.	one of these
Answer» D. one of these

Discussion

41.	Tides are complied and they vary from place to place because of ________
A.	he movement of Moon in relation to Earth
B.	neven distribution of water over the globe
C.	rregularities in the configuration of oceans
D.	ll of the above
Answer» E.

Discussion

42.	If the difference in time between, two places were 2 hours and 20 minutes, then the difference in their longitudes would be ________
A.	0°
B.	5°
C.	0°
D.	5°
Answer» C. 0°

Discussion

43.	Which of the statements given are correct? 1. Coriolis effect is zero at the Equator.2. Coriolis effect is more towards the Poles.3. Coriolis effects are related to the decreasing rotational velocity with increasing latitudes.4. Coriolis effects are related to the increasing rotational velocity with increasing latitudes.
A.	, 2 and 3
B.	and 3 only
C.	, 2 and 4
D.	and 5 only
Answer» D. and 5 only

Discussion

44.	Evidence suggests that life on Earth has existed for about ________.
A.	.5 million years
B.	5 billion years
C.	5 million years
D.	.5 billion years
Answer» E.

Discussion

45.	Which of the following statements is correct ?1. All meridians are of the same length2. All latitudes are of the same length3. The Prime Meridian is the longest meridian4. The Equator is the longest latitude
A.	and 2
B.	and 3
C.	and 4
D.	and 4
Answer» E.

Discussion

46.	Solar eclipse occurs when ________
A.	arth comes between sun and moon
B.	oon is at right angle to the earth
C.	oon comes between sun and earth
D.	un comes between moon and earth
Answer» D. un comes between moon and earth

Discussion

47.	Summer Solstice in the Southern Hemisphere occurs on ________
A.	1st December
B.	1st September
C.	1st June
D.	1st March
Answer» B. 1st September

Discussion

48.	In the earliest days when life originated on earth, the atmosphere contained ________
A.	ree oxygen
B.	o oxygen
C.	xygen in fixed form
D.	xygen bound to carbon
Answer» E.

Discussion

49.	Which of the following are true regarding equinoxes? 1. They occur on March 21st and September 23rd2. They depict equal days and equal nights on March 21st and September 23rd on all places of the earth3. All places on the earth have equal temperature during equinoxes.
A.	and 2 only
B.	and 3 only
C.	and 3 only
D.	, 2 and 3
Answer» B. and 3 only

Discussion

50.	Sea tides show variations because of ________
A.	ariations in gravitational pull of the moon
B.	ariations in gravitational pull of the sun
C.	istorted spherical shape of the earth
D.	ifferent phases of the moon
Answer» E.

Discussion

Explore topic-wise MCQs in Geography.

For a sandy soil having an angle of internal friction 30°, the ratio of passive and active lateral earth pressure will be

A retaining wall with vertical back retains a mass of cohesion-less soil, surface of which is level with top of the wall. Active lateral earth pressure coefficient (in terms of 'ϕ') i.e. angle of internal friction of backfill is given by:

A 6 m high retaining wall with a vertical back has a backfill of silty sand with a slope of 10° for the backfill. With values of KH = 760 kg/m2/m and KV = 100 kg/m2/m, the total active earth pressure will approximately be

A retaining wall retains a sand strata with ϕ = 30° up to its top. If a uniform surcharge of 12 t/m2 is subsequently put one the sand strata, then the increase in the lateral earth pressure intensity on the retaining wall will be

A homogeneous gravity retaining wall supporting a cohesionless backfill is shown in the figure. The lateral active earth pressure at the bottom of the wall is 40 kPa. The minimum weight of the wall (expressed in kN per m length) required to prevent it fromoverturning about its toe (Point P) is

An earth-retaining structure may be subjected to the following lateral earth pressures:1. Earth pressure at rest;2. Passive earth pressure;3. Active earth pressure.The correct sequence of the increasing order of magnitudes of these pressures is

How much increase in pressure will be, if a uniform surcharge of 120 kN/m2 is placed on the back fill with Φ = 30°

If the lateral pressure on a retaining wall is high, the following measure are taken while designing:

According to the level of pressure applied, lateral earth pressure is classified into various types. Which of the following type of lateral earth pressure refers to the minimum pressure exerted by the soil on the retaining wall?

Due to excessive pressure of the retained soil, the retaining wall tend to move:

For cohesion less soil particles, the neutral pressure coefficient of soil is taken as:

Given that for a soil depositK0 = earth pressure coefficient at restKa = active earth pressure coefficient Kp = passive earth pressure coefficientμ = Poisson’s ratioThe value of (1 - μ )/ μ is given by

A wall 6 m high has a smooth vertical back and retained sand as a backfill that is submerged. The sand has Ysat = 20 kN/m3 and ϕ = 30º. The total active earth pressure is

If top of earth retained is horizontal, the coefficient of passive earth pressure for retaining wall become:

Poisson's ratio of a soil sample is 0.4. Using theory of elasticity, the estimated value of the coefficient of lateral earth pressure at rest in the same soil is:

An excavation is to be made in a saturated soft clay (ϕu = 0) with vertical sides. What will be the maximum unsupported depth of the vertical cut?Given that cohesion intercept = 30 kN/m2, unit weight of clay = 15 kN/m3

What is the approximate equatorial circumference of the earth?

Which one of the following is the correct sequence of the given continents in the decreasing order of their percentage of Earth's land?

Owing to the equatorial bulge and the polar flattening, the polar radius of the earth falls short of the equatorial radius by about ________

Which of the following countries are located on the Greenwich Meridian?1. Algeria2. Germany3. Guinea4. Iceland

The place which has the longest day and the shortest night on 22nd December, is ________

The distance between two consecutive longitudes (91° E and 92° E) at the Poles is

The point below the surface where an earthquake originates is called ________.

The axis of rotation of earth is tilted by 23.5° to the plane of revolution around the sun. The latitude of Mumbai is less than 23.5° whereas the latitude of Delhi is more than 23.5°. Which one of the following statements in this regard is correct?

The deflection of the winds to the right in the northern hemisphere is caused by

The position of the earth in its orbit, when it is at its greatest distance from the Sun causing summer in the Northern hemisphere is ________

When does tides rise in sea?

The location of a place A is at 60° E longitude and 30° S latitude while the location of B is at 60° E longitude and 45° N latitude. Time at B will be ________

The Contour line is those imaginary line which show?

Low tides are

After Sun, which is the closest star to the Earth?

If it is 4 P.M. on Monday at 150°W, what will be the time at 150°E ?

Lunar eclipse occurs on ________

Which among the following imaginary line lies at 0° latitude?

Which of the followings are related with "Lithosphere"?

Tides are complied and they vary from place to place because of ________

If the difference in time between, two places were 2 hours and 20 minutes, then the difference in their longitudes would be ________

Evidence suggests that life on Earth has existed for about ________.

Which of the following statements is correct ?1. All meridians are of the same length2. All latitudes are of the same length3. The Prime Meridian is the longest meridian4. The Equator is the longest latitude

Solar eclipse occurs when ________

Summer Solstice in the Southern Hemisphere occurs on ________

In the earliest days when life originated on earth, the atmosphere contained ________

Which of the following are true regarding equinoxes? 1. They occur on March 21st and September 23rd2. They depict equal days and equal nights on March 21st and September 23rd on all places of the earth3. All places on the earth have equal temperature during equinoxes.

Sea tides show variations because of ________