Class 10 cbse
Question: Draw the ray diagram in each case to show the position and nature of the image formed when the object is placed:
(i) at the centre of curvature of a concave mirror
(ii) between the pole P and focus F of a concave mirror
(iii) in front of a convex mirror
Explanation:
I hope it will help you. But I am in Grade nine .And sry too cuz I told the answer of Grade nine .
3. Write any two differences between contact force and not contact force with examples.
Explanation:
Contact force includes applied force, the normal force, the tension and the frictional force. Non-contact force includes electro-magnetic force, the gravitational force and the electrostatic force. For Example, applied force is required to kick the ball else the ball would not move.
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Answer:
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A car moves with an average speed of 45 mph. How long does a car take to travel 90 miles?
Answer:
It took 2 hours
Explanation:
[tex]{ \bf{time = \frac{distance}{speed} }} \\ [/tex]
distance is 90 miles
speed is 45 miles per hour
[tex]t = \frac{90}{45} \\ \\ t = 2 \: h[/tex]
Answer:
2 hours
Explanation:
45 times 2 is 90
what is the relationship between high frequency and short wavelength? Low frequency and long wavelength?
Answer:
The frequency of a wave is inversely proportional to its wavelength. That means that waves with a high frequency have a short wavelength, while waves with a low frequency have a longer wavelength.
Which characteristic accounts for the fact that red lights in dark rooms and DO NOT expose negatives during developing?
Answer:
the long wavelength and not focused on the negatives.
what are each layer on an atom
Explanation:
Protons electrons and neutrons
13 The pressure of the atmosphere is 100 000 Pa
a Calculate the force with which the atmosphere presses on the outside of a large window 2.0m
high and 1.25m wide.
bExplain why this force does not break the window.
Question:-
(A) The pressure of the atmosphere is 100000 Pa Calculate the force with which the atmosphere presses on the outside of a large window 2.0m high and 1.25m wide.
(B) Explain why this force does not break the window.
Answer:-(A)
As we know
[tex]Formula -> pressure = {force} \times area[/tex]
Given->
Pressure-> 1atm
height-> 2 m
wide -> 1.25 m
Putting value in formula ->
[tex]100000 = force \times(h \times w) \\ 100000= force \times 2 \times 1.25 \\ force = \frac{100000}{2 \times 1.25}\\ force = {4×10000}\\ force = 40000\: newton \: (N)[/tex]
(B) Because atmosphere is present on both sides of the window pane so same force is applied from both sides of the window and as we know force is a vector quantity so according to the vector sum the force got cancelled out and net force becomes zero .
That's why even in presence of this amount of force window glass donot break
a) The force with which the atmosphere presses on the outside of the window be 3 × 10⁵ Newton.
b) As the atmosphere exerts thus much force on either side of the window, the opposing forces cancel one another out. The window is not broken by this force, therefore.
What is pressure?It is the ratio between the force being applied and the surface area being applied to. Pressure can be described as: the force applied perpendicularly to an object's surface divided by the surface area over which it is applied.
Given parameters:
The pressure of the atmosphere is 100000 Pa
Height of the large window: h = 2.0 m.
Width of the large window: d = 1.5 m.
surface area of the window = h×d = 2×1.5 m² = 3.0 m².
Hence, the force with which the atmosphere presses on the outside of the window = pressure × surface area
= 100000 Pa × 3.0 m².
= 3 × 10⁵ Newton.
b) As the atmosphere applies this amount of force in both side of the window, each two each an opposite force nullifies each other. So, this force does not break the window.
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What is the kinetic energy of a bicycle with a mass of 16 kg traveling at a velocity of 5 m/s
Answer:
200J
Explanation:
K.E=½mv²
K.E=½×16kg×5m/s²
K.E=8kg×25
K.E=200J
Nikki has a momentum of 45 Kilogram meters per second and a mass of 30 Kilograms. What is her velocity?
Answer:
45/30
Explanation:
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Nikki has a momentum of 45 Kilogram meters per second and a mass of 30 Kilograms. then her velocity would be 1.5 meters per second
What is momentum?It can be defined as the product of the mass and the speed of the particle, it represents the combined effect of mass and the speed of any particle, and the momentum of any particle is expressed in Kg m/s unit.
Mathematically the formula of the momentum is
P = mv
where P is the momentum of the particle
m is the mass of the particle
v is the velocity by which the particle is moving
As given in the problem Nikki has a momentum of 45 Kilogram meters per second and a mass of 30 Kilograms
P = 45 Kilogram meters per second
m = 30 Kilograms
By substituting the values of the momentum and the mass in the formula of the momentum
P = mv
45 = 30 ×v
v = 45/30 meters per seconds
v = 1.5 meters per seconds
Thus, Nikki weighs 30 kilograms and moves at a 45 kilogram per the second momentum. subsequently, her velocity would be 1.5 meters per second.
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Jan is 1.32 meters tall. What is her height in inches?
Answer:
51.96 inches
Explanation:
Multiply 1.32 by 39.37
Answer:
52.0 inches
Explanation:
1.32 meters * 39.37 = 51.96 inches ~ 52.0 inches
Is ambition a good or bad thing?
Answer:
some amount of ambition is good for your motivation but excess ambition is dangerous.
Class 9 SCIENCE
ch 2 Is matter around us pure
Question -
what you mean by crystallization? Give example.
Answer:
Crystallization is defined as a process by which a chemical is converted from a liquid solution into a solid crystalline state.
write si units of the following physical quantities volume , potential difference, temperature, electrical resistance
Answer:
cubic meter - Volume
Volt - potential difference
kelvin - temperature
ohm - electric resistance
Explanation:
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When 4050 joules of heat were applied to 150g of aluminum, the final temperature was 50 degree Celsius. What was the initial temperature? Take specific heat capacity of aluminum as 900J/kg degree Celsius.
Answer:
[tex]\boxed {\boxed {\sf 20 \textdegree C}}[/tex]
Explanation:
We are asked to find the initial temperature of aluminum. We will use the following formula.
[tex]q= mc \Delta T[/tex]
Where q is the heat energy, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature, which is also the difference between the final and initial temperature.
[tex]q= mc (T_f-T_i)[/tex]
We know the heat energy applied is 4050 Joules, the mass is 150 grams, the final temperature is 50 degrees Celsius and the specific heat is 900 Joules per kilogram degree Celsius.
We must convert the mass to kilograms because the specific heat is in kilograms. 1 kilogram contains 1000 grams.
[tex]\frac { 1 \ kg }{1000 g }[/tex][tex]150 \ g *\frac{ 1 \ kg }{1000 g } = 150 * \frac {1}{1000} \ kg = 0.150 \ kg[/tex]Substitute all the known values into the formula.
q= 4050 J m= 0.150 kg c = 900 J/g °C [tex]T_f[/tex]= 50°C[tex]4050 \ J = (0.150 \ kg )(900 \ J/kg \textdegree C)(50 \textdegree C -T_i)[/tex]
We are solving for the initial temperature, so we must isolate the variable [tex]T_i[/tex]It is being multiplied by 0.150 kilograms and 900 Joules per kilogram degree Celsius. The inverse operation of multiplication is division, so we divide by both values.
[tex]\frac {4050 \ J}{ (0.150 \ kg )(900 \ J/kg \textdegree C)}= \frac{(0.150 \ kg )(900 \ J/kg \textdegree C)(50 \textdegree C -T_i)}{(0.150 \ kg )(900 \ J/kg \textdegree C)}[/tex]
[tex]\frac {4050 \ J}{ (0.150 \ kg )(900 \ J/kg \textdegree C)}=(50 \textdegree C -T_i)}[/tex]
The units of Joules and kilograms cancel.
[tex]\frac {4050 }{ (0.150 )(900 \ \textdegree C)}=(50 \textdegree C -T_i)}[/tex]
[tex]\frac {4050}{135} \textdegree C = (50 \textdegree C -T_i)[/tex]
[tex]30 \textdegree C = (50 \textdegree C -T_i)[/tex]
50 degrees Celsius is being added to [tex]-T_i[/tex]. The inverse operation of addition is subtraction. Subtract 50 degrees Celsius from both sides.
[tex]30 \textdegree C - 50 \textdegree C= 50 \textdegree C - 50 \textdegree C - T_i[/tex]
[tex]-20 \textdegree C = -Ti[/tex]
[tex]T_i[/tex] is being multiplied by -1. The inverse operation of multiplication is division. Divide both sides by -1.
[tex]\frac {-20 \textdegree C}{-1}= \frac{-T_i}{-1}[/tex]
[tex]20 \textdegree C = T_i[/tex]
The initial temperature of the aluminum was 20 degrees Celsius.
Abishek is a runner. He runs the 100 m sprint
in 10 x 6s. What speed did he travel at?
(in m/s)
Answer:
1.67m/s
Explanation:
Total Distance to be travelled by a Runner=100m
Time Taken=10*6s
Speed=Distance/Time
=100/10*6=10/6=1.67m/s
The answer you are looking for is approximately 1.67 m/s.
Solution/Explanation:
Distance Ran: 100 m.
Time ran: 10x6s, or 60s, or one minute.
Speed: Unknown?
Writing out the formula for speed, using distance and time,
S=D/T.
S=Speed.
D=Distance.
T=Time.
Substituting the given values of the variables,
S=100 m/10x6s, or S=100 m/one minute, or S=100 m/60s.
100÷60=1.6667≈1.67.
So, therefore, the final answer is approximately 1.67 m/s.
I hope that this has helped you. Enjoy your day, and take care.
A cyclist travels at 15 m/s during a sprint finish. What is this speed in km/h
Answer:
54km/hr
Explanation:
Since we have to complete m/s to km/h.
we can simply divide the m/s by (5/18)
so we get 54km/hr
10th grade Physical Science.... Help plss
1.) Which option is a negatively charged ion?
A) chloride
b) chlorate
c) chlorite
d) chlorine
2.) When moving across a period from left to right in the periodic table, excluding transition elements, which trend occurs?
a)Valence electrons increase by one.
b)The energy levels increase by one.
c)Valence electrons decrease by one.
d)The energy levels decrease by one.
3.) Which information about an atom can a period number give you?
a)the number of valence electrons it has
b)the ionic charge it forms
c)how many bonds it will make
d)how many energy levels it has
4.) Fluorine has 7 valence electrons. Which charge is its ion likely to have?
a)5+
b)1–
c)5-
d)1+
5.)Which two elements in the list would bond together based on their ionic charges?
a)calcium and potassium
b)potassium and iodine
c)calcium and neon
d)potassium and neon
Use the list to answer the question.
potassium, Group 1
calcium, Group 2
iodine, Group 17
neon, Group 18
The periodic table is an arrangement of elements into groups and periods based on their periodic properties. Elements a placed in these groups and periods.
1) A negatively charged ion is chloride
2) Moving from left to right, valence electrons increase by one.
3) The period number gives information about how many energy levels it has
4) Fluorine has a charge of 1–
5) Potassium and iodine form an ionic bond.
In the periodic table, elements are arranged in groups and periods. There are 18 groups and 8 periods.
Chlorine is in group 17, there have seven outermost electrons hence the chlorine atom needs only one more electron in order to attain a stable octet. This is done by accepting one electron to form the negatively charged chloride ion.
As we move from one period to another, one extra electron is added to the outermost shell of elements. Hence, the valence electrons increases by one.
The period to which an element belongs shows you the number of shells or energy levels in the atom of that element.
Fluorine is in group 17. One electron is needed to achieve a stable octet. When an atom accepts one electron, its charge is 1–.
Bonding based on ionic charges occurs between metals and nonmetals. Potassium is a metal of group 1 and iodine is a non metal of group 17 hence they can bond together based on their ionic charges.
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help me please i dont understand
Answer:
inertia is due to friction
True or false? Balanced forces cause a change in motion. T/F
How do you know this?
Help me, it's due soon!
Balanced forces do not change the motion of an object, Because the forces are the same size and acting in opposite directions.
Answer:
Balanced forces do not change the motion of an object. The motion of an object will not change if the forces pushing or pulling the object are balanced. An object that is sitting still will stay still if the forces acting on it are balanced.
which of the following are fundamental unit ?
I.candela
II.ampere
III.mole
IV.all of these
Answer:
all of these very easy questions
b Write out the following in full:
103 2 x 106 6.92 x 104 1.34 x 102 10
Can somebody help?
Answer:
b
Explanation:
define physical quantity
Answer:
The quantity which can be measured is called physical quantity.
Answer:
Those quantities which can be measured are called physical quantities.
A car starts from rest and accelerates uniformly at a rate of 8.0 meter per second squared for 1.0 meters. At the end of this time interval, the car's final velocity is ___ meters per second.
Answer:
The answer is [tex]v=4ms^{-1}[/tex]
Explanation:
Given,
[tex]u=0\,ms^{-1}\\a=8\,ms^{-2}\\s=1\,m\\\\v=?[/tex]
We know,
∴[tex]v^{2}=u^{2} +2as\\=>v^{2} =0^{2} +2*8*1\\=>v^{2}=16\\v=4\,ms^{-1}[/tex]
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Which types of changes must follow the law of conservation of mass?
Both physical and chemical changes
Neither physical nor chemical changes
Only physical changes
Only chemical changes
Answer:
Both physical and chemical changes
Answer:
Both physical and chemical changes follow the law since when the system is closed to all transfers of matter and energy, the mass of the system must remain constant over time, irrespective of the state.
Explanation:
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1.If a wooden cube has length and breadth of 1.5 m each and it is exerting a pressure of 1200 pa. What is it's weight (f)?
Explanation:
Explanation:
Pressure is defined as a Force over an
Area.
p=F/A
We can rearrange this to make the Force
the subject
F = p *A
The pressure is given as 1200 Pa.
We know a pascal is 1 Newton / Square
metre = N/m²
The area of a cube will be width * breadth
= 1.5 m * 1.5 m= 2.25 m²
So the force the cube is pushing down
with (its weight) is simply
F = p * A = 1200 N/m² * 2.25 m² = 2700 N
Weight is officialy defined as a force
measured in Newtons, but when we
talk about weight we often give it in
Kilograms (a unit of mass).
To get the weight in units of
Kilogram-force you must divide by the
gravitational acceleration =9.81 m/s²
2700 / 9.81 = 275.23 Kg
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Actividad
1: En general, la dificultad para arrancar electrones aumenta de izquierda a derecha en cada periodo de la tabla periódica. Busca en la tabla periódica potasio (K), calcio (Ca) y uranio (U) y basándote en sus posiciones indica cuál de ellos tendrá una función de trabajo más baja y cuál más alta:
Menor función de trabajo:
Mayor función de trabajo:
2.- La energía de un electrón emitido se mide en electrón-voltios(eV). Un electrón con una energía de 1 eV puede superar un campo eléctrico de 1 voltio. En el simulador, aumenta la tensión hasta que encuentres la tensión más alta que todavía permite a los electrones llegar al amperímetro.
Tensión =
El volaje que has encontrado es igual a la energía de los electrones emitidos en eV.
4:36 PM
How high can a human throw a ball if he can throw it with initial velocity 90 kph
Answer:
90 km/hr= 90000/3600=25 m/s initial velocity
-25/ 2 (-4.9)= 2.551 secs
h(2.551)= -4.9 (2.551)² + 25(2.551)=-31.8872449+63.775 = 31.8m
The distance would be 31.8 meters, also that person will have sore arm.
After 14.1s, a jogger's displacement is 520m. What is the average velocity in km/h
The average velocity in km/hr is 132.99km/hr
The first step is to convert 14.1 secs to hours
14.1/3600
= 0.00391 secs
Convert 520 m to km
520/1000
= 0.52 km
Velocity= displacement/time
0.52/0.00391
= 132.99km/hr
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34.1 grams / 1.1 mL =
General formula,
→ 1 mL = 1 gram
The given question is,
→ 34.1 grams / 1.1 mL = ?
According to the formula,
→ 34.1 grams / 1.1 grams
→ 34.1 ÷ 1.1
→ 31 grams
The answer is 31 grams.