1) Light can be reflected, absorbed, or refracted when interacting with mirrors and lenses. The law of reflection states that the angle of incidence equals the angle of reflection.
2) For a flat plane mirror, the image location is the same distance behind the mirror as the object is in front. The image is virtual, upright, and the same size as the object.
3) Concave mirrors can focus light to a real, inverted, and enlarged or reduced image location that can be calculated using the mirror equation. Ray diagrams and calculations of magnification can determine full image characteristics.
Presentation on Various ideologies and concepts of Light.
Assessment for class X students for 2nd term.
With highly elaborated information on Light and it's properties.
100% Most Accurate Presentation on Light chapter Class X CBSE..
With Transitions and animations..
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Presentation on Various ideologies and concepts of Light.
Assessment for class X students for 2nd term.
With highly elaborated information on Light and it's properties.
100% Most Accurate Presentation on Light chapter Class X CBSE..
With Transitions and animations..
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
2. Facts about Light
It is a form of Electromagnetic Energy
It is a part of the Electromagnetic Spectrum and the only part we
can really see
3. Facts about Light
The speed of light, c, is constant in a vacuum.
Light can be:
•REFLECTED
•ABSORBED
•REFRACTED
Light is an electromagnetic wave in that it has wave like properties
which can be influenced by electric and magnetic fields.
4. The Law of “REFLECTION”
The Law of Reflection states that- " the angle
of incidence (incoming ray) equals the
angle of reflection (outgoing ray)"
The law works for FLAT,
PLANE surfaces only.
The angles are measured
from a perpendicular line
to the surface called a
NORMAL.
NORMAL
5. Plane Mirror
Suppose we had a flat , plane mirror mounted vertically. A candle is
placed 10 cm in front of the mirror. WHERE IS THE IMAGE OF
THE CANDLE LOCATED?
mirror
Object Distance, Do = 10 cm
Same side as the object?
On the surface of the mirror?
Behind the mirror?
6. Plane Mirror
Suppose we had a flat , plane mirror mounted vertically. A candle is
placed 10 cm in front of the mirror. WHERE IS THE IMAGE OF
THE CANDLE LOCATED?
mirror
Object Distance, Do = 10 cm Image Distance, Di = 10 cm
Do=Di, and the heights are equal as well
Virtual Image
7. Virtual Images
Virtual Images are basically images which cannot be
visually projected on a screen.
If this box gave off
light, we could project
an image of this box
on to a screen
provided the screen
was on the SAME
SIDE as the box.
You would not be able to project the image of the
vase or your face in a mirror on a screen, therefore
it is a virtual image.
CONCLUSION: VIRTUAL IMAGES are ALWAYS on the OPPOSITE side of
the mirror relative to the object.
8. Real Image
Real Images are ones you can project on to a screen.
For MIRRORS they always appear on the SAME SIDE of the mirror as the object.
object
image
The characteristics of the
image, however, may be
different from the original object.
These characteristics are:
•SIZE (reduced,enlarged,same
size)
•POSITION (same side,
opposite side)
•ORIENTATION (right side up,
inverted)
What if the mirror isn’t flat?
9. Spherical Mirrors – Concave & Convex
Also called CONVERGING mirror
Also called DIVERGING mirror
10. Converging (Concave) Mirror
A converging mirror is one that is spherical in nature
by which it can FOCUS parallel light rays to a point
directly in front of its surface. Every spherical mirror
can do this and this special point is at a “fixed”
position for every mirror. We call this point the
FOCAL POINT. To find this point you MUST use
light from “infinity”
Light from an “infinite”
distance, most likely the
sun.
11. Converging (Concave) Mirror
Since the mirror is
spherical it technically
has a CENTER OF
CURVATURE, C. The
focal point happens to
be HALF this distance.
We also draw a line through the
center of the mirror and call it the
PRINCIPAL AXIS.
f
C
C
f
2
2
12. Ray Diagram
A ray diagram is a pictorial representation of how the
light travels to form an image and can tell you the
characteristics of the image.
Principal axis
f
C
object
Rule One: Draw a ray, starting from the top of the object, parallel to the
principal axis and then through “f” after reflection.
13. Ray Diagrams
Principal axis
f
C
object
Rule Two: Draw a ray, starting from the top of the object, through the focal
point, then parallel to the principal axis after reflection.
14. Ray Diagrams
Principal axis
f
C
object
Rule Three: Draw a ray, starting from the top of the object, through C, then
back upon itself.
What do you notice about the three lines? THEY INTERSECT
The intersection is the location of the image.
15. Ray Diagram – Image Characteristics
Principal axis
f
C
object
After getting the intersection, draw an arrow down from the principal axis to
the point of intersection. Then ask yourself these questions:
1) Is the image on the SAME or OPPOSITE side of the mirror as the object?
Same, therefore it is a REAL IMAGE.
2) Is the image ENLARGED or REDUCED?
3) Is the image INVERTED or RIGHT SIDE UP?
16. The Mirror/Lens Equation
Is there any OTHER way to predict image characteristics besides
the ray diagram? YES!
One way is to use the MIRROR/LENS equation to
CALCULATE the position of the image.
i
o d
d
f
1
1
1
17. Mirror/Lens Equation
Assume that a certain concave spherical mirror has a
focal length of 10.0 cm. Locate the image for an
object distance of 25 cm and describe the image’s
characteristics.
i
i
i
o
d
d
d
d
f
1
25
1
10
1
1
1
1
16.67 cm
What does this tell us? First we know the image is BETWEEN “C” & “f”. Since the
image distance is POSITIVE the image is a REAL IMAGE.
Real image = positive image distance
Virtual image = negative image distance
What about the size and orientation?
18. Magnification Equation
To calculate the orientation and size of the image we
use the MAGNIFICATION EQUATION.
x
M
M
h
h
d
d
M
o
i
o
i
67
.
0
25
67
.
16
Here is how this works:
•If we get a POSITIVE magnification, the image is
UPRIGHT.
•If we get a NEGATIVE magnification, the image is
INVERTED
•If the magnification value is GREATER than 1, the
image is ENLARGED.
•If the magnification value is LESS than 1, the image
is REDUCED.
•If the magnification value is EQUAL to 1, the image
is the SAME SIZE as the object.
Using our previous data we see that our image was INVERTED, and REDUCED.
19. Example
Assume that a certain concave spherical mirror has a focal
length of 10.0 cm. Locate the image for an object distance of
5 cm and describe the image’s characteristics.
5
1
5
1
10
1
1
1
1
i
i
i
i
o
d
M
d
d
d
d
f
-10 cm
2x
•VIRTUAL (opposite side)
•Enlarged
•Upright
Characteristics?